In my opinion it would be a sin to modify that car!

 

BizJet,

I have an 89 Formula that I am gathering the DD swap for. I only need harnesses. I have yet to touch the car though and would consider a complete swap dash and all harnesses with you. I would like to have spares of the DD boards. Do you have digital HVAC too? I do need all that.

Dude I just saw that I am only 45 min from you in Boynton. We need to talk!

Cheers, Tim

 

TallTim - I just picked up a 1989 Formula 350 - so i think I am going to be selling the GTA - let me think about it a couple days and I will let you know.
We should meet up at Cars & Coffee in WPB sometime - Thanks

 

Please show some pictures of the Formula! Did you find it locally? I searched for a year and found mine in DC 1K away from me. Of course in S FL everything is at least 1K away....

 

As I go through this thread again. I really wish I had a easy test set/code loader that I could just attach to my laptop via usb. I have no idea how I would load these files onto the chips.

 

BRAVO. You certainly have helped a lot of people out who can understand all this. I believe we could possibly have made a woman out of a barbie bv back in the 80s! Obviously, I would have brought the Barbie & you would have done the rest....
GREAT WORK!!!!
Now to be able to apply it.

 

Hi everyone, great tread. I know the last tread was long time ago. But I need help with my odometer board. I need to know what is this part and if it's possible to replace a broken one for a new one.

I identify it on a previous picture posted here, at the beginning. Sorry for that.

 

Looks like a potentiometer

 

The part pictured in a orange circle is a Power Transistor....PNP or NPN. They are availabe. Just pull the numbers off it and order one

 

Thanks for the information. I will check for one of those. I hope this fix my odometer.

 

Is hard checking for the transistor numbers. Any help with this information.

one.

 

Just google the numbers on it listing a transistor. Or go to a electronics store. ..computer repair and such. Mouser, Digikey, any of them, Radio Shack...

 

Thanks for the information.

 

Maybe my google skills are severely lacking but I spent half an hour searching for a 5 pin TO-220 package IC and came up empty. Can you take close up pictures of the board to see if we can make out what the purpose of that chip was and find an alternate part that way? The part was made by National Semiconductor.

 

I found some information about that:

NSC drawing: To50
Order number: LM2931CT.

Now the part is from Texas Intruments.

 

Hey Cehbra,
this is so great. I have the 999999.0 odometer and need a new chip. Are you able to ship me one?

Best regards,
Stuart.

 

This is great info! My odometer is currently flashing and hopefully this will help me resolve the issue. for some reason I cannot send a private message yet, didnt figure out the process. @Cehbra, do you have anymore chips for sale?

 

hello
I have problem with my odometer, it flashes 999999.9. Is that broken /fixable or what? Car dont have original ecu, but does this need it anyway? This car has been sleep past 16years because engine fire. And now it is rebuild almost ready, and can test with battery. There were missing few grounding what I put there. And now dash seems to be Ok, but this odometer… also those buttons wont do anything

 

I am interested in this topic I have a 1984 trans am I'm going to be swapping in an 87 digital dash into and my car has 32k miles and this new dash i am putting in had around 167k miles. It would be nice to know how to change this dash to the right milage

 

My computer didnt load the rest of the post and I just read it and wow there is so much useful information. Is there any way I can still buy one of the chips and have it programmed to save me the trouble? If not i would be fine sending the one I have in to be changed. Thanks

 

Interested in a programmed chip, if still available.

 

Good morning ,
I am writing this way because otherwise I cannot contact Cehbra. I read very carefully the wonderful "fight" with the digital counter and I have a similar problem. I have a 1990 Pontiac Grand Prix and I bought digital clocks for it. Everything is OK, but of course there is a problem with the mileage of the car. My original mileage is 153,000 km and the mileage on digital clocks is 220,000 km. Of course, there was a need to set this mileage to the correct value. However, there is another EPROM there. The symbol of this memory is 25072478 REV D. The housing is DIP 16. Is it possible that this is the same memory as in this case, as described by Cehbra?

 

Dear readers

I've recently done two repairs of Trans Am clusters in Stockholm, Sweden.
Several problems have been addressed and finally found solutions for.
First customers main complain was that the E/m button would only switch between miles/ km on the odometer and would not transfer to the speedometer.
The second customers complain was that the cluster was unreliable, it would boot sometimes and sometimes not.

Reset signal was sorted and pulled low after replacement of the top right tantal on the odometer board

Stable supply voltage was achieved after replacement of the TO-220-5 transistor, we found that the LM2935 is a drop in replacement after lots of digging in 1986-ish data books.
(The TO-92 transistor above prom can be replaced with a standard NPN signal transistor 2N3904 will work just fine)

The switching signal from odometer to speedometer would work just fine and output high/ low signal while odometer board was by itself, when the speedometer was connected the signal would stay high all the time.
We create a small pcb with a Schmitt Trigger to boost the signal and this would solve the problem on the first cluster.

Happy about a working solution for the first cluster, we implemented the Schmitt Trigger board with no luck at all!
The signal would wiggle between 1.2-1.5 volt instead of 0-5 volt low/ high. We tried several methods to sort this issue: pull-up resistors, pull-down resistors, capacitor cleaners, nothing would help,
Next we tried a comparator circuit that would switch the outputs to 0/5v on a certain threshold value, hen connected the threshold value would move to another most likely due to the load changing.

The next tactic was to use the switch and trigger a new design circuit to output a high/low signal. we choose a flip-flop solution and with a Schmitt Trigger/ reset circuit to make the start signal low or high every time.
This made the circuit and cluster working 100%!

thanks for reading.
(the pictures are of the schmitt-trigger board on the speedometer board as well as the Switch board, please do reach put to us if you need any of the boards or repair help)



SPEEDOMETER ATTACHED PCB

ODOMETER ATTACED PCB
​​​​​​​

 

Resurrecting this thread to see if anyone out there is still repairing these dashes. My odometer flashes on and off. I have a spare and it does the same thing.

 

Replace board and screen. Transfer OD chip

 

I have a spare board and chip and it does not make a difference. The odometer just flashes on/off. No clue what the odometer of the car is to register it into my name.

 

If the chip has garbage data in it (in other words its corrupted), the Odometer will just flash on and off with the mileage at 999999.9. None of the buttons on the Odometer will work either. You will have to reprogram the chip to clear the error, unless something is wrong with the microcontroller and not the mileage chip.


I bought a 1988 GTA new back in the day (sold it in 1993) and have at least one spare digital dash (maybe two) still in my garage. I have ordered some PCBs to build up a programmer for the mileage chip (NCR 52801) that is used in these clusters (2801Prog from 2801Prog Rev. 1 MCM2801 and NCR 52801 EEPROM Programmer | D'Asaro Designs (dasarodesigns.com)).


The PCB's will take a few weeks to get to me, and I have to get together the parts to build one (or more) up.


Once I have the programmer built up, I plan on trying to read the mileage chip in my cluster(s) in the garage and using Cehbra's (username on this forum) program that he created to decode the memory chip and give me the mileage: https://www.thirdgen.org/forums/atta...2801decode.zip


I suppose after that, I could be persuaded to read your memory chips and see what mileage data is on them, or if they are even valid. I could also re-program the chip(s) and put on the correct mileage for your car and resolve the Odometer error with the flashing and the 999999.9 mileage reading.


Regards,


Xenawise

 

That would be great.If you get the programmer going let me know and Id gladly get you to reprogram my chips.

 

I have all the parts to make the Programmer and am just waiting on the PCB(s) to get to me from China. They are now in the USA and should hopefully get to me by the end of this week. Will take a day or two to build one up and test it. I have also purchased some spare NCR52801 chips (I ordered 12 of them) to have some spares for those folks that don't want to send me their chips or their chips have failed to the point where they can no longer hold the programmed information. These chips are almost unobtanium at this poiont and they were not cheap, but then again, they were not too expensive. When I do end up selling a chip to someone, just plan on the cost for the chip to be around $50 programmed or not. If I re-program your chip, plan on the cost for that to be around $25. This is a hobby for me so I am not trying to run a business re-programming these chips, but I think there is a small need for this as time goes on and I would like to help for as long as I can.

I do plan on making a few programmers available for sale and am thinking the cost for one will be around $75. Just wanted to let you guys know the cost up front so you can decide if this is worth it to you or not. I can't do it for free as it will take up some of my time and as they say, time is money. But I think the cost for this is very reasonable.

Comments or questions? Please post them up!

Regards,

Xenawise

 

Built up two 2801 Programmers for the NCR52801 EEPROM chip used in the 1985-1988 Pontiac Firebird Digital Dash.

Now I am waiting on the USB-A to RS232 Cable as well as the 12 NCR52801 chips I ordered both of which should be arriving today. I also need to program the microcontrollers used in this project and get them installed into the socket(s) on the PCB(s). So should not be long before I know that these work and then after that I need to get my Digital Dash out of the garage and try the chips in the Digital Odometer to make sure the programmed chips actually work.

Regards,

Xenawise

 

So I got the NCR52801 chips in as well as the Driver Genius USB-A to RS232 cable to connect to the 2801Prog Programmer. Most new PCs don't have a serial port anymore, so you need a cable like the Driver Genius to give you COM port to hook up old serial devices to. Here are some pictures of the programmer and lots of screen captures of the software:


This is the gEEProg 2.0 software that was designed to be used with these programmers. This screenshot is when you first run the program. Note on the bottom it says, "Select the appropriate serial port to begin." I need to select COM4 in my case as that is the port the Driver Genius cable was given by Windows 10.

Here is gEEProg 2.0 connected to COM4 and it detects the 2801Prog programmer.

Here is gEEProg 2.0 after a read of the NCR52801 chip. I had previously programmed it with the 1234567890ABCDEF sequence you see in the buffer on the left-hand side of the screen. So, it properly read the chip contents.

Here I am erasing the chip and the gEEProg 2.0 program says it has completed the chip erase. This will put all logic zeros in all the chips memory locations.

Now we read the erased chip and see the buffer now shows all zeros (00) in every location.

Now let's try PUDDY and talk to the 2801Prog directly with a Terminal program. This way we don't need to use gEEProg to control the 2801Prog programmer. We can use a simple terminal program to use the programmer. Here I am setting up the COM port, Baud rate, Data bits, Stop bits, parity and flow control.

I open up a terminal window with PUDDY and it is just blank. Lets plug in the 2801Prog programmer and see what happens.

Here is the terminal window after the 2801Prog programmer is powered up. Looks like things are working as expected.

Here is the help file. It shows all the commands used with the 2801Prog programmer.

Now let's read the chip, and then display what we read...

You can see it read back all the zeros from when we used gEEProg 2.0 to erase the chip. Now lets fill the buffer with some data and program it into the chip...

Here we are erasing the chip once more, then programming the chip with the data in the buffer from the previous screenshot, and then we read back the data we just programmed and finally display the data we read from the chip which is now in the buffer. Notice that the data in the buffer after the read is the same data we had put into the buffer to program into the chip. Suffice to say everything seems to be working as it should.

 

Now let's start up the Encode/Analyze software that allows us to create the data to program into the NCR52801 chip to make the odometer in the digital dash read the correct mileage....

Here is the analyze screen where you can analyze a chip in an existing cluster (after reading the data off it using the 2801Prog programmer and one of the previous software packages...

Let now program a chip with the mileage 2468. Due to idiosyncrasies with how the algorithm works, you can only put in mileage in 10-mile boundaries. Here you see the dialog box that explains that we must select one of the mileage options provided.

I picked 2475 in this case. Now the program gives us the data we need to program into the chip to indicate 2475 miles displayed on the odometer. You can easily clip it to the windows clipboard for use in the gEEProg program. The PUDDY terminal window will not accept a cut/paste of the clipboard so we would need to type in each byte one at a time. This can lead to errors so if you do use PUDDY, double and triple check your buffer before programming.

Finally, lets paste the code the program provided into the analyze portion of the program and see what mileage it decodes. As expected, it decodes 2475 miles which is what will display on the digital odometer in the vehicle.

We have come full circle now with being able to read and program the chip used in the digital odometer (the NCR52801 EEPROM) as well as being able to decode mileage in the chip (probably corrupt if you are getting the 999999.9 flashing mileage) and program in any mileage we want displayed on the odometer and correct those that have the 9999999.9 flashing corrupt mileage chip. The chip just could have corrupted data in it from sitting unused for decades or it might actually be a bad chip unable to be programmed anymore. I purchased 12 chips for those cases where the original chip proves to be bad.

I also have 8 more programmers I can build (at the time of this posting) along with the two that I already built and tested. Of course I will be keeping one programmer for my use, but the rest should be available if you would like to get one to be able to do this yourself.

Any questions or concerns or comments, please let me know!

Happy 3rd Genning!

Regards,

Xenawise

 

Oh, forgot the Programmer picture and a picture of the chips...






Regards,

Xenawise

 

Thats fantastic, I'd like to buy one of your programmers and maybe one of your NCR chips? I am from germany but I have a US shipping adress.

 

Hello J.C. Denton from Germany! I lived in West Germany back in 1979-1982 when I was just a pre-teen (11-14 years old) in the town of Hanau on the Pioneer Kaserne as my father was in the US Army stationed there. Glad to of seen the culture there and explore some of West Germany as well. I have looked at Google Earth from time to time as see much has changed in that area since the US left the area. Lots of good memories living there.

I am glad you are interested in the programmer. I think it best to take this to PM so we can work out all the details.

Regards,

Xenawise

 

Would you be willing to sell me 2 pre-programmed chips that i can repair my existing displays with?

 

Hello 86White_T/A305. I would be willing to sell you 2 pre-programmed NCR52801 chips that should repair your existing odometers. Price for the first chip is $50. Since you are getting two chips at the same time and I can program them together, I'll knock 20% ($10) off the second chip for a total of $90 plus shipping. Let me know if this is agreeable to you. And if these chips don't fix your odometer issues, I'll refund your money and pay for shipping to get the chips back to me.

Also, if you would like to send your old chips to me if indeed the new ones fix your issues, I would pay you $5 per chip plus shipping. I would like to have some old chips as well to see if they still take any programming or if they have bad memory locations or if they are just bad. Let me know what you decide.

Regards,

Xenawise

 

That works for me. PM me and we can workout the details for payment and shipping.

 

Xenawise, message sent

 

Can you help me as I too want to change the odometer reading on a GTA I am getting as I will be swapping in an LS Motor and am extremely interested in swapping in a Digital Dash instead of the boring Analog one. How can you change the odometer reading?

 

DoniZ_22

The mileage is kept on an EEPROM memory chip in the digital dash. There is a programmer that was made that read and write information to this chip. Cehbra reverse engineered the algorithm that is used to keep the mileage and wrote a program to encode and decode the data on the mileage chip. Using the programmer for the NCR52801 chip used to keep the mileage and the program Cehbra wrote you can change the mileage to whatever you want and to fix those odometers out there that perhaps the chip has gone bad in as the odometer just flashes 999999.9 miles.

As for swapping a digital dash into a car with the analog cluster, there are a few other related threads that go into detail on how this can be done. Probably best to get the entire dash carrier out of a doner car with all the wiring. The big issue will be getting the DIC (Driver Information Center) working as there are unique wiring that allows that module to read if the headlights and taillights are burned out (using resistance wiring) and things like washer fluid level and coolant level sensors that were not in the cars with the analog cluster.

Regards,

Xenawise

 

OK folks,

I sent forum user 86White_T/A305 two programmed chips. When he got them, he tried them, but the odometers still just flashed 999999.9. He decided to send three sets of odometers (LCD and PCB) and see if I could see what was wrong. I got my Digital Dash out of my garage and hooked it up. It worked fine and displayed 58055.0 miles. I noticed that the LCD on my odometer has some segments missing. I was not sure if the LCD was damaged (it looks OK), or of the odometer chip was bad.

Once I got the parts from 86White_T/A305, first thing I wanted to check was the LCD. So, I took one of his LCDs and plugged it in my odometer PCB. His LCD worked perfectly. So, my LCD is faulty. I mean it works, but a few of the segments of the number don't work, and the RESET, TRIP ODO, AVG SPEED and MILES annunciators don't seem to work either. In any case, good to know that my odometer PCB was fine.

Now onto the task of testing his chips. I took them out of his odometer PCBs one at a time and tried them in my Odometer PCB. To my surprise, they all worked just fine. Come to find out 86White_T/A305 left the new chips in two of the odometers so that helps explain why those just worked. The third odometer PCB had an original mileage chip installed, but that one too just worked.

Now, I found the original chips he took out and replaced with my programmed chips. One of the chips actually worked but reading it on the programmer did show some corrupt bits, and with multiple reads some of these bits would actually change. Not enough corruption to make it not work apparently. So, I erased the chip multiple times and reprogrammed it multiple times and it seems to be just fine.

The last original chip was indeed corrupt. The odometer would flash 999999.9 with this chip installed. I read it on the programmer, and it mostly zero bits with a few others with some values in them. But decoding the bits showed that they were all corrupt. So, I erased the chip, and it erased successfully. I programmed the chip with valid mileage information and then erased and programmed multiple times and the chip seems to be holding the information just fine. Not sure the longevity of the chip, or how it got corrupted to begin with, but it seems to be working fine now.

So, looks like all three of 86White_T/A305's odometers are working fine. Not sure why he was getting 999999.9 issues. Now, my testing is on the bench with only the odometer PCBs, so these odometers are not installed into the cluster and attached to the flex PCB that runs to all the parts of the cluster. The only other input to the oedometer is the VSS speed signal and a lamp dimmer input for the Switch stack that is connected to the odometer PCB (has English/Metric, AVG Speed, TRIP Odo and RESET switches) and this has a #73 light bulb installed to backlight these buttons. The lamp is burned out, and I had to take apart the switch stack and clean all the button contacts as none of the buttons really worked except the English/Metric button. They switch contacts had oxidation on the contact points so cleaned off the oxidation and the switch stack works like new now. I need to get a #73 lamp to replace the burned out one so the backlighting will work again as well.

The LCD also has an orange diffuser that the lamp on the back of the cluster that backlights the odometer LCD shines through to give it that orange color. One of 86White_T/A305's LCDs was missing this diffuser, so I am thinking that maybe some florescent orange gel filter might work in this case. Gel filters are used mainly for stage lights to change the color. But gel filters are very clear so you could see the light bulb behind the LCD, so maybe a white sheet of paper between the LCD and gel filter would help to diffuse the light and spread it more evenly across the LCD display and make it so you can't see the lamp behind the LCD. I will see if I can get some gel filter approximately in the same color as the original and see if this would work to replace the missing one. The other original diffusers are not in the greatest shape either (with stains in the visible area) so if this works it might be a good idea to replace them all.

So, good news really. All three of the odometers 86White_T/A305 sent to me seem to be functioning just like they should be. At least on the bench.

Regards,

Carl Miles

 

This is awesome. I appreciate the effort you put into this and how fast you are on respond and try things out.

Full disclosure to everyone else. I pulled the engine and transmission out the car before I could test the new chip I was sent. I had 1 for sure functioning odometer at that point and 2 spares I wanted to try.

After getting the chips, I put then in the 2 spares. I rigged up temp power to the car to test them. I don't know if I damaged the ribbon on the cluster during removal or installation but none of the odometers would display anything now. Just backlight, the buttons did not respond to anything like trip.. Reset etc. This was on the functioning dash before the motor was pulled. I tried the other 2 clusters with all 3 odometers and same results.

Fearing I just ruined not only a good cluster.. But now 3 odometers and the chips I received. I offered to send them all to be tested in another car/cluster and eliminate any errors there.

Now I know the chips/boards are good. Onto further testing.

 

So cleaned up my Digital Dash Cluster after taking it entirely apart to allow me to start testing the odometer PCBs and their respective LCD displays actually installed in the cluster. Here are the results:

Odometer PCB & LCD #1 Miles displayed:


Odometer PCB & LCD #1 kilometers displayed (note the speedometer also switched to km/h when using the E/m switch):


Short video on cluster power on with Odometer PCB & LCD #1 installed:
https://drive.google.com/file/d/16x-...ew?usp=sharing


Odometer PCB & LCD #2 Miles displayed (note this is with the damaged original LCD diffuser installed so you can see how the damage looks):


Odometer PCB & LCD #2 km displayed (note this is with the damaged original LCD diffuser installed so you can see how the damage looks):



Odometer PCB & LCD #2 Miles displayed (note this is with an orange matte gel filter installed - you can see the point source of the backlighting, so we need more diffusion of the light):


Odometer PCB & LCD #2 km displayed (note this is with an orange matte gel filter installed - you can see the point source of the backlighting, so we need more diffusion of the light):


to be continued...

 

Odometer PCB & LCD #2 Miles displayed (note this is with an orange matte gel filter and a light diffuser from a bad monitor LCD display installed - you can see the backlighting is more diffused and looks pretty good and close enough to factory):


Odometer PCB & LCD #2 km displayed (note this is with an orange matte gel filter and a light diffuser from a bad monitor LCD display installed - you can see the backlighting is more diffused and looks pretty good and close enough to factory):


Short video of cluster power on with Odometer PCB & LCD #2 installed (note this is with an orange matte gel filter and a light diffuser from a bad monitor LCD display installed - you can see the backlighting is more diffused and looks pretty good and close enough to factory):
https://drive.google.com/file/d/11jw...ew?usp=sharing



Odometer PCB & LCD #3 Miles displayed (note this PCB & LCD did not have a factory diffuser so this is with an orange matte gel filter and a light diffuser from a bad monitor LCD display installed - you can see the backlighting is more diffused and looks pretty good and close enough to factory):


Odometer PCB & LCD #3 km displayed (note this PCB & LCD did not have a factory diffuser so this is with an orange matte gel filter and a light diffuser from a bad monitor LCD display installed - you can see the backlighting is more diffused and looks pretty good and close enough to factory):


Short video of cluster power on with Odometer PCB & LCD #3 installed (note this is with an orange matte gel filter and a light diffuser from a bad monitor LCD display installed - you can see the backlighting is more diffused and looks pretty good and close enough to factory):
https://drive.google.com/file/d/1vC1...ew?usp=sharing

And finally, a picture of the segment check on my personal Odometer LCD display. Notice the TRIP ODO, AVG SPEED, RESET, MILES and km on the bottom are messed up and some of the number segments don't work)
Anyone have a spare Odometer LCD they might have to replace mine?)


Well, suffice it to say, the three PCB & LCD Odometers sent in to me to check out are all working as intended. I don't have a TACH and VSS (Vehicle speed sensor) simulator currently (working on building one) that would allow me to increment the mileage on the Odometer to further fully test the memory chip keeping the new, updated mileage. But, other than that, I think these Odometers should work just fine in an actual car.

Let me know if you have any questions or comments!

 

Well, 86White_T/A305 wanted to know how I was hooking my cluster up on the bench to test it and get these pictures so he can do the same at his home and test to make sure the Odometers work correctly as well as the cluster and then decide if there is a cluster wiring issue (with the printed circuit on the back of the cluster) or if there is an issue with the car instrument cluster wiring harness.

When I took those pictures, I had the cluster hooked with a bunch of alligator clip jumper wires and it was a bit precarious. Any second one or more of them could fall off or worse yet short out to another clip. So, the past few days I have been working on getting a female connector that will fit into the clusters connectors and provide a much more reliable and safe way of connecting to the cluster:

The Alligator Clips:


Homemade Connectors:


Plugged into C1-C3 leftside connector:


Plugged into C2 rightside connector:


Backside shot with connectors plugged in:

 

Also, something that I have been working on is a Cluster Tester and DIC Tester. This will plug into the cluster and allow you to (with individual switches) turn on or off any of the lamps in the cluster (example: Left Turn Signal, Service Engine Soon, SECURITY, Choke) as well as the individual power circuits (Ckt39 and Ckt950). You can turn the memory power to the odometer on or off,

There is a built-in Vehicle Speed Sensor (VSS) generator and Tachometer signal generator so you can feed actual signals into the cluster and see the speedometer show an actual speed (along with incrementing the odometer mileage) and see the tachometer display showing RPMs. These generators are fully adjustable so you can dial in the RPM and Speed you want.

You can also check the gauges (Fuel, Oil Pressure and Coolant Temp) with selectable values that should show the minimum, middle and maximum values that the gauge can display to verify that your gauges are reading correctly. There is also a selection for fully variable control so you can set any value you would like and see how the cluster gauges respond.

Technically, this could be used with other GM instrument clusters as well (and possibly other manufactures clusters as well) as I have made the connection to the cluster on the PCB as a plug in so you could make up different "dongles" to plug into the bench tester for other clusters since at least GM uses mostly the same values for fuel, oil pressure, coolant temp, Tach and vehicle speed for clusters in the 1980's, 1990's and into the 2000's. At least before data bus clusters. But then again, the sensors didn't really change, so you could feed the signals into the data bus cluster and maybe get it to read the sensors. Now, powering up these data bus clusters is another matter. Probably would have to get a Body Control Module to make that work.

One last thing it can check, is the Driver Information Center (DIC)! The one used in the Trans Am / GTA dash was also used in the Grand Am as far as I know (I had both cars back in the day, actually still have a 1986 Grand Am LE in the backyard - my cars were a 1988 GTA (bought new) and a 1987 Grand Am SE).

The DIC can test all the seven inputs including lamp outage and dimming! Forgot to mention this will control the dimming on the cluster as well!

Here is a shot of the PCB. I know it's kind of busy, but hey, there's a lot of stuff needing to be checked on these clusters and DIC!:






This is just a prototype, but I will have to get 5 PCBs made because the PCB House has a quantity 5 minimum. So, there is the possibility a few of these will be for sale if you are interested. Probably won't be too cheap, but the potential is there.

Imagine hooking this up to a power bank that can put out 12VDC and you have a portable cluster tested that you can take out to the garage or even the junkyard and test clusters in the field before you buy! Like I said, you could make "dongles" for different clusters so you could test more than the Trans Am / GTA digital cluster. You could test the analog clusters as well!

Let me know your comments and questions!

Regards,

Xenawise

 

As for what pins to hook up to test the Odometer on the bench, in my case I hooked up all the +12V lines and grounds to the cluster. This allowed all the displays to function. I think as a bare minimum, you would want the following hooked up:

Connector C3 (White) top row:

Pin G (7) - Speedometer Ground
Pin F (6) - Speedometer +12V

This will allow the Speedometer display to work (you can see the MPH and km/h change)

Connector C2 (BLACK)

Pin 16 - Odometer +12V
Pin 21 - Odometer Memory +12V
Pin 24 - Odometer Ground

That will get the Odometer to work. But we need the backlighting to see the display, so that comes from what it looks like to be the Fuel Gage electronics so to get that to work:

Connector C2 (BLACK)

Pin 12 - Fuel Display Ground
Pin 13 - Fuel Display +12V

And I think that should do it.

How I hooked it up as mentioned I hooked up all the +12V and grounds to the cluster so to do that you would need the additional connections:

Connector C3 (White) top row:

Pin C (3) - RPM Display +12V
Pin D (4) - RPM Display Ground
Pin L (11) - Lamp Ground for turn signals and high beam lamps - probably not needed unless you want to light these lamps up

Connector C2 (BLACK)

Pin 1 - Lamp power for SES Lamp, BRAKE Lamp and internal hidden generator lamp - probably don't need unless you want to light these lamps up (same as Pin 27 - connected together in the factory harness)
Pin 8 - Lamp Ground for SES Lamp, BRAKE Lamp and internal hidden generator lamp - probably don't need unless you want to light these lamps up
Pin 27 - Lamp power for SES Lamp, BRAKE Lamp and internal hidden generator lamp - probably don't need unless you want to light these lamps up (same as Pin 1 - connected together in the factory harness)
Pin 31 - Gages Display Ground
Pin 32 - Gages Display +12V

So, a total of eleven (11) wires needs to be hooked up the cluster for full operation. Possibly seven (7) for the Speedometer, Fuel, Odometer and the LCD Backlighting to work (RPM and Gages Display won't function with just seven wires).

Hope this helps!

Regards,

Xenawise

 

Where did you get those connectors?

 

Really cool! I'd like to have a bench test unit too!