ChristinaMarie

Re: Instrument Cluster Help
We acquired a 1991 RS Camaro that was an original V6 car. The previous owner did a V8 swap. The installation was far from perfect. We had to put a complete engine harness in the car, and now because they hacked the dash cluster harness to install an after market digital dash cluster, we are unable to use the digital dash for accuracy. We have purchased a 91 dash cluster off ebay to replace the digital one. We had an 89 donor car that we used the connectors to marry the cluster to the wiring harness. Through trial and error, we have been unable to get the dash cluster to work. We have used the pinout diagram as a guide to ensure wires are correctly placed. Here are my questions:

1. Is the connector from the 89 compatible with the dash cluster from a 91? It seems to fit..but the plugs do not seem to want to stay connected to the cluster. I have looked online, and cannot find the answer to this question.

2. I read the sending units may be the cause..but i need more information about this. I read that if you do an engine swap, the sending units will not match the dash cluster. The post stated that we would need to find the correct sending units for motor. Does anyone know about this?

3. If you have any suggestions on what the problem could be, any feedback would be appreciated!!

ChristinaMarie

Is anyone seeing this?? I'm not sure I did this correctly!!!! Lol

SbFormula

What connector are you talking about? What plugs do not want to stay?

The sending units have to match the cluster year/model for accuracy. There are the CT and Oil pressure for the dash cluster

What is "unable to work"? The entire dash cluster?

You would have to check every wire that goes to the dash cluster and match them with the a dash cluster function. Once figured out it's a matter of wiring it. This could be nerve racking and time consuming. If the prior owner tempered with the wiring, you won't probably be able to rely on a diagram. The color code could be very handy though.

I am curious as to what kind of ECM the prior owner put in place for the swap. Was the swap for a 350 TPI or TBI or some after market intake?

This wiring business is not an easy fix.

Best of luck!

ChristinaMarie

Hi SbFormula! Thank you for replying. I never usually post so I wasn't sure from the lack of response if I did it right! Lol I figured there was no easy fix for this! Can't understand for the life of me why someone would go to all the trouble of installing a dash if they were only going to rig it to work 20%!

SbFormula

Not easy you say? You need patience and investigative skills!!! :-)

ChristinaMarie

When I say " connectors", I'm referring to the piece that holds the wiring that u connect to the back of the cluster. One holds wiring for drivers side, and one for the passenger side. There are two prongs on each end that I assumed U would squeeze in while placing inside the back of the cluster. When I place it in there and release the prongs, it does not click In place. So I was U sure if the connectors are generic or were specific to the year of the cluster..(connectors were from a cable driven cluster from an 89 ..cluster I bought off eBay is a 91). The engine is a 305 TBI. We are quite confident that judging by the way they cut so many corners on this car, that when they installed the digital dash, they cut most of the wiring from drivers side, and connected basically the fuel and ground.. Nothing else worked. T
I am confident that the sending units were not installed as well. That was why I figured going back to original would have been easier...far from it! Before we attempted to swap out clusters, all accessories worked, so now on top of the dash not working, the ACC fuse keeps blowing out. So now we are checking voltage in cluster to be sure we have the 12 v needed..then check grounds. Then..start all over again.

ChristinaMarie

Lol! Patience went out the window after more than 7 hours of looking at the pinout ..then wires...then pinout again...then wires..then poof!! ...went the fuses! Frustration set in then I needed to walk away for a bit!

Scorpner

iTrader: (4)

I was going to reply earlier but I'm not sure how much I can help. I didn't notice at the time that you posted an image and even now I can't open it.
The clusters from 1989 to 1991 are shaped differently, and each fit into the dash surround that matches it. GM often retains the specific electrical plug ins, but the pin outs are often different from year to year, and also different within the same year due to many variances like manual/auto, V6/V8, among many other factors. That would be found by comparing pin outs from year to year and also different models.
There is also a difference in the sensors from warning lights to gauges and also after-market gauges. Then, you say that both the engine and dash harness, ...and possibly the structure of the dash has been hacked/modified, it becomes more difficult to reply because there are so many variables.

Reply for #1: The connectors may fit but from what I recall the surround and/or screws holding the cluster to the dash may be what holds them together. I know that you can't access the plug-ins unless you remove the cluster, so that tells me that they wouldn't stay attached on their own as you are describing (at least not very well).

Reply for #2: Yes, even if you go through the trouble to actually trace the wiring to say the temp sensor, that particular sensor is probably for the after-market gauges previously installed (or even idiot lights) vs. the sensor your replacement cluster needs. If you know what car your cluster came from (year/model/engine etc.) then that should indicate what sensors you need. then go to the store and take a chance at buying them and testing them before installing if you can. It may help to know that the gauges are basically little meters and the sensors vary in resistance which are read by the gauges, so by knowing that you can test each individually if it comes down to it. Also note that the V6 and V8 clusters are not easy to tell apart and I especially don't know about 91-92 clusters, but I know in general you can often tell by the tachometer red line marking. So just in case later on you notice that the tach is off, that may be why.

In all, if you have a 1991 RS that was a V6 but now has a V8, and the dash has been physically cut up to fit after-market gauges, you are going to end up with some interpolation to get it to work. I would suggest going to a local junkyard that allows you to remove what you need to get the job done. I'm not sure if that would include replacing the entire dash or cutting part of it out and trying to reattach it (which gets into hacking it again), plus you may end up with difficulty securing the plug-ins again if said patch doesn't hold. Depending on how much was done, a new dash and engine/dash wiring harnesses you may be much better off imo. Please try posting pics again if possible.

Edit: It sounds like you have a short somewhere and I would get that taken care of separately and right away before proceeding with the cluster.

SbFormula

Yep it is frustrating.

First off the connectors don't clip. They stay in place by pressure once the dash is screwed in place. Check out the pics on this forum, It should look like that

https://www.thirdgen.org/forums/elec...gas-gauge.html

A 1989 connector could physically fit a 1991 but the wiring could be different.

Then get a good volt tester and have the negative black wire hooked to an extension wire so you can hook it to the battery negative. Use the other red positive wire to test. Make notes and rely on the color code to guide you. Some wires won't be testable because they are pulsation or just grounds.

For the following I will give you connector numbers but make sure you locate the wire color as the position on the connector could be inaccurate.

A)Some wires are grounded by the ECM to activate a warning light. It means 12Volts is present at the light and once grounded by the ECM it activates. If ECM was tempered with, it might not be working anymore. The V6 MPFI ECM and the TBI ECM are different
Connector C1: 2,10,11 are grounds to ECM
Connector C1: 1 is ground to Airbag module
Connector C1: 9 is 12 volts with key at on position (can be tested with voltmeter)

B)Some wires are also grounded by a switch. 12 volts present and grounded to activate.
Connector C1: 6,12 are grounds to seat belt buckle and hand brake pull
Connector C2: 5,6,8 are ground to flasher switch and high beam switch
Connector C1: 9 is 12 volts with key at on position (can be tested with voltmeter)
Connector C2: 14 is 12 volts with key at on position (can be tested with voltmeter)

C)The temp, oil and fuel gauges need 12 volts and a ground + ground to the sensor
Connector C1: 4 is ground to CT temp sensor on engine head
Connector C2: 3, 4 are grounds to oil sender on engine and fuel sender in fuel tank
Connector C1: 9 is 12 volts with key at on position (can be tested with voltmeter)
Connector C2: 14 is 12 volts with key at on position (can be tested with voltmeter)
Ground connector C1 is 3,5
Ground connector C2 is 2,7,12

D) Volt gauge needs 12 volts and ground
Connector C1: 9 is 12 volts with key at on position (can be tested with voltmeter)
Connector C2: 14 is 12 volts with key at on position (can be tested with voltmeter)
Ground connector C1 is 3,5
Ground connector C2 is 2,7,12

E)The speedometer and tachometer need 12 volts and ground to function as well as a signal wire
Connector C1: 7 Tach signal from distributor
Connector C2: 1 Speed signal. In 1991 model the speedometer was driven by a electronic module not a cable.
Connector C1: 9 is 12 volts with key at on position (can be tested with voltmeter)
Connector C2: 14 is 12 volts with key at on position (can be tested with voltmeter)
Ground connector C1 is 3,5
Ground connector C2 is 2,7,12

F)Dash illumination is driven by 12 volts when parking light switch is activated.
Connector C2: 13 is 12 volts when parking light on (can be tested by voltmeter)
Ground connector C1 is 3,5
Ground connector C2 is 2,7,12

So really the only test possible with a voltmeter is C1-9, C2-14 and C2-13.
You need to find the short first. The ACC 20A fuse is related to C2-13 the dash lights. C1-9 & C2-14 have another fuse 10A for gauges.

Best of luck!

Scorpner

iTrader: (4)

This link is as close to an image of what the inside of a cluster housing should look like in case yours is cut apart. It appears to be an earlier Camaro but shows how the connectors are held in place.

https://www.thirdgen.org/forums/elec...ml#post4399456

Actually, I just found a 1992 dash here:
https://www.thirdgen.org/forums/elec...ml#post5167162

Oh, that was the same one SbFormula posted. lol

ChristinaMarie

Thank you all so much for your help! Will keep U posted!

DonW

I just went through this....what a PITA!!!! I tore (what was left) of the clusters printed circuit completely out and made my own harness and wired direct!
My speedo is mechanical, so that worked...but that was about it. There are 3 wires to identify for the fuel level gauge. Isolating those and connecting them directly to the gauge itself fixed the fuel level issue. Aftermarket oil, water, and temp guages fixed the remaining gauges as they come with their own senders. For cluster lighting I went to advance auto parts and lo and behold they sell single LED bulbs with two leads coming from the bulb (a hot and a ground) Comes in either white or blue. I grabbed several packs of the blue bulbs and replaced the stock cluster lights with these blue LED's. Your headlight switch has an unused port on it that a spade connector fits pefectly on. Feed a wire from there, through an inline fuse and use it to power the new LED bulbs and presto! After I saw that everything worked flawlessly I took it back out and made a good looking harness to quick disconnect everything and put all wires in a loom. I can remove the cluster easy enough that way should I ever need to take it back out. The best part is that the new lighting being LED draws a fraction of the amperage from the headlight switch that the stock lights did. Heres a pic of the setup..... Those are bosch mini gauges...no modification to the gauge bezel was needed...they fit right in there but I did have to bore the gauge cluster itself with a paddle bit to get them to sit deep enough. Not my normal way of doing things, but hey....all of the wiring was cut when I got it, emissions removed, computer controlling nothing etc....it was the logical way to go.

DonW

Left a few things out of that post as I also had to identify the turn signal wires and high beam indicator light and wire it into my new harness, but everything works and is safe. The next owner if there ever is one shouldnt cuss me too badly...lol He only has to disconnect one connector to remove the gauge cluster (after he gets passed the bezel anyways...lol