go to the link below, and only pay attention to the last 4 or 5 posts http://www.thirdgen.org/techboard/bo...light=gremlins

Couldn't a relay be wired up to get "B" and "A" to connect to each other by using the power from "C"? All you want is B&A to connect to each other when A/C switch is on, right?

Anyone? Are the B&A wires really needed? A relay will make B&A functional.

Here's how. "C" is wired to both the a/c controls and this relay. When "C" is switched on by the A/C controls, it will also give power to the relay. When the relay energizes(has ground and power across it), it closes the switch inside and connects B to A.

Yah, I had thought of the relay. If you know where to find the relay, let me know.

I had a few extra from the LT1 swap and then a few more extra from the dash swap. Any relay meant for a car, with 4 wires will work, even 5 wires will - just don't use the 5th wire(87A wire). Any auto store sells them too.

my gauge lights arent working.

i also have lt1 gauges, but my tach is kind of jumpy i have 350 also. would hooking up to msd box fix this?

if your tach is jumpy, you have a loose connection somewhere.
could be power into the cluster or the tach wire itself.

power into the cluster?

it idles fine, but when i give it a shot of gas it seems its revving higher then the motor really is, thats all i meant by jumpy.

You need a Dakota Digital Tachometer calibrator.

ok so if i had a msd box it wouldnt read correctly either?

if your car is a v8 and you have a v8 cluster, etc. you shouldnt need a box. but there are exceptions.
years of clusters. v6 cluster, ls1 cluster etc.
see if everything is right before you buy a box and still have the same problems.
an msd will not fix your problem either. one of their tach adapters might work.
all depends.
what motor and cluster are you running. etc... ?

im running 350, the tach is supposedly from 95 lt1.

350 as in carb'd or efi?
you run run a carb setup, and you 100% have a v8 cluster, you dont need a box, AFAIK. one wire, should work awesome.

yeah its carbed. but when i rev it, it seems so floppy revvin up... quicker then it should.

the guy could have lied to me about the tach being v8. it idles at 800rpm just like it should.

if it wasnt a v8 cluster, idle wouldnt be at 800. somethings loose or damaged somewhere along the line.
ive seen and done it strait to a stock tach before with no trouble.
good luck.

im having a problem with the dash, everything is ok. But for the bolts that hold the dash to the firewall at the top, if i have the farthest one on the passenger side and the middle one and TRY to put the driver side one in the screw doesnt even reach the dash. I have to put stress on it for it to go in, and i did. The next morning the passenger side dash bracket cracked and popped out.

ok i need some big help with the wiring up of my lt1 cluster i have read everthing i could find took down notes anything to get these to work but i get nothing none of my gauges will move i think after i cut out my factory connectors i had three wires left over that i could not find a place for maybe a dark brown and a green i think not sure but shouldn't i see something working ar least?

dark brown x 2?
is it dark gree? could be your vehicle speeed sensor, or coolant temp sensor?

if you hooked them up right, did you hook up the 3 grounds underneath the steering column?

ok double checked on whats left and there was two dark brown wires then another dark brown with a white stripe and a geenish one left

the 2 x brown isnt used. i dont see another brown one, you sure its not dark grey?

the green could eitther be high beams, coolant temp. its just green right no green with black stripe which is your speedometer if its not a cable.

it might be dark gray if it is whats it go to? i thought the two tanish wires went to the speedo?

there are 2 x yellow, 2 x brown, and 2 x tan/black

tan/black x 2 = skip shift indicator

yellow x 2 = ses light

ok after rechecking my third gen wiring i have 2 dark gray wires another dark gray with stripe and a green wire with black stripe those wires are whats left from my factory connectors

green with black stripe is your speedometer

dark grey i didnt use, but there was only 1 dark grey, there are a couple other grey wires they are for illumination but are more lighter then the dark grey.

did you ever come up with anything on this because i test fitted mine yesterday and seen the same thing? but any way thanks for all your help roughskinjrz i seem to have the gauges working but the high beam light but im having the jumpy tach problem and i have tryed an ls1 and two different lt1 clusters and get the samething so i started on the headlight switch and now im hung-up on that my factory switch has a orange,red 2xyellow,gray,and white wire and the 4th gen plug was a orange,red,pink,yellow,and a gray or brown wire plus a thin black and gray wire but i figured that those two thin ones where for the light but maybe i was wrong!

ok got the headlight switch working right but not the dimmer switch and i have no lights on my gauges and still the jumpy tach to get straight yet!

haven't made it on here much recently, rough....the dash isn't going to fit on the drivers side, the curvature of the two types of cars (3rd to 4th gens) are different. What i'd do is use a spacer to take care of the distance between the mounting flange and the dash, this'll keep stress points to a minimum, and also allow you to still use the mounting tab. See what you can find to fix that other mount, if you can't find anything, glue it , and reduce any strain on it also. Best of luck, with all the time i've spent with this car, i still don't have my dimmer switch working, but then again, havne't driven or seen the car now in about 2 months. very sad.

I have been wanting to do the swap for awhile and was wondering if anyone could tell me what year dash and cluster would match up best with my 87 305 carb trans am i was also wondering what i would need to get in the way of vss or dakota box. Any help would be appreciated

I know this is a old post, but I havent found anything that says how the 3rd and 4th get vent assb. are tired together. thats to only thing I am having issues with trying to figure out how to get the air into the 4th gen dash assb.

Just try and cut the 4th gen vents in the back until they match up somewhat. Mine aren't perfect but I think I'm going to try running ac ductwork from home depot or something then use padding to keep air from leaking.

i was thinking about that also, but the vent system is so much diff on the 4th gen. the 92 ac box outlet is angled and the 4th gen duc work is straight. I am using a 95 dash. I quess I will figure something. thanks for the info

you just have to trim the center vent outlet from the 4th gen to same fashion as that used on the third gen, use your thirdgen vent as a guide, or make a template of the different pieces of the 3rd gen unit w/ cardboard, trace, and cut away...size wise the a/c reciever area (center part) is about the same as the 3rd gen unit, and it works pretty well...

I did get it in and wired, for some reason the brights wont turn off. well when the lights are turned on anyway

I got a problem... Wiring up my 4th gen headlight switch and dimmer switch is not working out too well... Here are the colors that I have to match up, yet I'm not sure where they go.

From my third gen side to the 4th gen side here is what I got.

Third gen headlight switch...
red
orange
black
brown
yellow
green
white

Then the 3rd gen dimmer switch...
light yellow?
purple
black
grey

Then on my 4th gen headlight switch the colors go like this...
red (x2)
orange
black
yellow
grey
brown

4th gen dimmer switch...
brown
green
black
grey

Please help me figure out which wires go where?

Alright ive gone through everything I could on this site, I havent slept in 24 hours just so I can get this stupid thing to work...

But I cant get any of my gauges to work, turn signals are a negative, cant get headlights, parking, dimmer etc to work... wtf am I doing wrong??

Car is a 91 RS V8.. Interior came out of a 95 V6... WTF is the problem im having??

Wires I got left are 1 brown, 1 yellow/black, 1 red, and 1 orange...

Gauges work.
Gas gauge just reads full when the car is empty (i know this for a fact since I ran it out)
Blinkers dont work
Cant figure out the wiring for the headlights...

Anyone??

And the reason my gauges wernt coming on was because I blew a fuse somehow...

I should be starting on the headlight switch tommorrow. Did anyone come up with a wiring diagram yet?
Thanks,
Kory

I have to wierd problems with my guages. When I turn my dimmer switch all the way to on to turn on interior lights my whole cluster lights up. Also when I turn on my headlights my fuel guage goes to empty, and it went up when I got gas so I believe its hooked up to the right one. I replaced the 3rd gen light switch with 4th already and just on both black connecters on 4th gen wired it to the on black one for the 3rd gen dimmer. Everything else seems to be working fine.

any updates on the wiring at all?

hey, sorry to cut in late on this thread, but i got an 87 iroc running a 305 ho tpi but eveythings set up for a 350tpi, and i might swap to a lt1, but i just got a dash from a 94, i got the dash, gauges, center, headlight switch, a couple other switches, hvac box, and some other stuff, now, im guessing that the speedo is cable driven. does anyone have a link on the converter box? i looked on their site, and didnt see much at all that would be useful. now i dont want to dig into my mostly o.e. car and mess things up beyond return, i want to get this dash swapped cheap and work fully. mounting and running the vents is no problem, but the wiring is what im worried about, now i gotta go get plugs for everything still, but is this just a wire and go thing pretty much, if i just follow the wiring guides on here will it all work out? along with the hvac box... how do i mod the lines up to work? like i said, i dont want to tear into this car unless i have all my stuff sorted out.
thanks in advance
keith

My car is a 92 V-8, T-5 car, the dash / cluster i have is from a 2000 SS, will this work? ive read somewhere that you had to use a firebird cluster? And since its a v8 car with a v8 cluster I DONT need the dakota digital box, correct?

can i use the harness from a 2000 SS and plug it into the 93-97 firebird cluster or do i need the 93-97 harness?

I have a 94 Dash and wiring harness in my 83 Z28, and everything works perfectly. Some issues I ran into during the project and solutions (applies to 93-95 donor dash);
- The 4th gen harness is difficult to get out of a donor car without cutting, as it doesn't have handy disconnects like the 3rd gen does. Take your time, use tape or some other method of identifying cut wires (makes life far easier!), and decide what you need to keep or discard by way of modules as you go, it saves a lot of time. If cutting wires, before re-connecting decide how you want to run the finished product in the car, and lengthen/shorten as necessary. This can make for a much cleaner and organized install over stock, and simplify troubleshooting. I used an entire 94 harness, modified it specifically for my engine bay routing and dash setup, and managed to hide all my wiring within my fenders and along the back bottom of my firewall, hidden from sight. I also incorporated the 4th gen engine relay box in my driver side front battery tray, allowing easy access to all my engine and main power fuses and relays. Also added was a 4th gen power distribution block just behind my battery on the passenger side, mounted under the coolant overflow bottle on the front of the wheel well. I also highly suggest soldering all wire connections, and sealing them in heat shrink tubing and wire looming wrapped in electrical tape. Remember to always check after connecting wires for continuity to ensure against a cold solder or bad connection. Electrical gremlins are the worst to be stuck on the side of the road with!
- The 3rd gen heater ducting will not work in all modes with a 4th gen dash. To have full climate function you must use a 4th gen heater duct, which means modifying your firewall for clearance. I've outlined this in another thread, with pictures and measurements. The system in my car has fully functional climate controls, so it is possible with some modification.
- The 93-95 cluster can use the 3rd gen Firebird yellow VSS buffer box to drive the speedo, using a stock 3rd gen electronic speed sensor and 700R4. No Dakota Digital box is required. Wiring is the same as wiring in the electric speedo for a 3rd gen (as outlined in the Tech articles section of Thirdgen).
- The tach on the 93-95 cluster can sometimes bounce if being driven off an HEI distributor, especially older units like the 4-pin style. This is because the LT1 computer has an inline signal buffer that cleans up the signal to the cluster, which the HEI does not provide. Installing either an inline diode to buffer the signal, or using an ignition box such as an MSD 6 or Mallory 6A and sourcing the tach input from it will correct the problem and provide a smooth tach signal.

Im having a horrible time finding a lt1 dash harness are the wires the same to the back of the v6 cluster? I have a lt1 cluster but can't find a lt1 harness to save my life

Cluster wiring is the same. I used a V6 harness on my car, deleting unused items (SRS, coolant level, ABS, etc) for my application, but all wiring locations to the back of the cluster are identical. A V6 and V8 cluster are interchangeable, with the exception that the tach will read incorrectly.