Hello guys. I recently picked up the complete setup for a digital dash for my 89 GTA (dash, bezel and all the necessary wiring/sensors). Now my question is does my 89 GTA have a VSS that the digital dash can get a singal from for the speedometer? I have a feeling the cable from the analog one is not going to work for the digital one, so does the transmission on my car have a VSS on it? Is it the same thing the cruise uses to get it's reading?

 

89 GTA should have a factory electric VSS. Trans Am Digital Dash cars used the same exact electric VSS.

 

Okay well that's great news. Now I want to know if anyone has the pin out diagrams of the 89 GTA analog dash so I can know where everything goes when I do the swap. I got the info on the digital I just need the pin out diagrams for the analog one.

 

I'm almost certain that ALL the D/D wiring harnesses are different. I'm sure the Engine, Body, Heater/AC, Dash, and Taillight harnesses all changed to accommodate the additional sensors/wiring required by the Digital Dash option.

Since all the wiring in a digital dash car is different than the wiring in an analog car, If you have all the digital car wiring, your good to go. If you don't have ALL the digital dash wiring I'd locate any wiring harnesses that you're missing rather than 'converting' the analog wiring... but that's me.

This is the C100 (firewall plug) for the 88; Should be similar in 89. You can see what wires are DD specific ( AKA: "lamp Monitor")




Here is the C207 ( ECM harness to dash harness ) info: Looks like no changes to those connectors but double check to be sure.

1988 C207 (should be 89 too)
PIN Color From / To (Notes)
A Brn ALDL (pin C) / ECM (AIR control)
B* Pnk (Red) INJ1 TBI (TBI)
B* Pnk/Blk (Pink) INJ1 (V6)
B* Pnk/Blk (Black) INJ1 (TPI)
C* Brn/Wht ECM / CE Light
D* Brown (Tan/Wht ) Fan
E Wht/Blk ALDL (pin B) / ECM (test)
F Pnk/Blk IGN fuse / ECM
G* Pnk/Blk (White) INJ2 TBI (TBI)
G* Pnk/Blk (Pnk/Black) INJ2 / (V6)
G* Pnk/Blk (Black) INJ2 (TPI)
H Tan/Blk ALDL / TCC-ECM (auto)
H Tan/Blk ALDL / Upshift (stick)
J* Org ALDL (pin E) / ECM
K Brn/Yellow (brown) ECM / Buffer
L Drk Blue (purple) Vats to ECM
M Blk/Wht VSS,P/N switch / Grd
N Org/Blk ECM / P/N switch
P
R Ppl/Wht Crank Fuse / Cold Start-ECM

 

Well hopefully I got everything. I'll let you know when the stuff arrives.

 

I'm with our friend John here , if you don't have 100% of the wiring from the donor car , you'll have to get the missing pieces . Sub harnesses ? Can we call the smaller pieces that ? Bonus points if pictures were taken of the dis assembly that these parts came from , but we all know the chances of that .

Anyway , good luck with it , and pictures of what you do would be great ...

 

All I can say is that if you don't have the entire harness from the donor car and you attempt to pin out the analog wiring you are a way braver man then I. Good Luck and I hope everything works out well.

 

Well I did a complete digital dash pin out swap of a 91 Ford Taurus SHO. Swapped out the stock analog to a digital. And it was a pin by pin, wire by wire swap. Even had to add a hole in the pcm for an additional pin. It's not hard. I just need some digrams of the analog pin out and I am confident that if (and I do mean if), I will just splice a few wires so I can fit in the new digital one. But first I need to see what there is. And I be sure to drop some photos.

 

This is not swapping and adding a few pins. There is specific digital dash only wiring and sensors throughout the car body for items such as lamp monitor, and sensors for doors, trunk, radiator and washer fluid. You will also need a special radiator and washer fluid bottle that have provisions for the fluid level sensors. Also, the digital gauge cluster does not just plug into the analog dash, the entire dash housing is also specific to digital.




Personally, I am not afraid of getting into any wiring job, but the only way I would do this swap is if I had a fully functioning digital dash car sitting there that I could gingerly remove the brittle parts myself. Hopefully you get every piece required, and that none of the plastic was broken at removal. That's a lot of faith to lay on another human, you don't want to piece this project together.


The swap can be done, but it's gonna be fairly involved. Good luck, and let us know how it turns out!

 

It's important to know what year the donor wiring is from too.

All Thirdgens in 88 (or so) had a re-designed wiring system. From 82-87 (or so) the dash harness ended on the drivers side behind the kick panel and was plugged into a "body" harness. But staring in 88 (or so) GM integrated the Dash Harness and the Body harness together into a single harness that ended where the tail light harness connects. ( IIRC This change occurred the same year GM re-designing the Engine and ECM wiring into a single huge harness. )

In other words; 87 Digital Dash wiring is not directly compatible with 88 Digital dash wiring so be sure that you know what vintage the wiring is if/when you need to get additional harnesses.

* If there is any digital dash wiring that might be similar for all years, The Heater/AC harness MIGHT be the same for all digital dash cars.

Peaked my interest !! Are you sure about that ?? The last time I stripped a digital dash housing I could have sworn that it was exactly the same after comparing it to a 'regular' Firebird housing. (Obviously, the Radio/Cluster Bezels changed; I'm asking if your sure about the actual Housing....... )

 

John: I have had an entire 88 digital dash apart, but have not had a non-digital on hand to compare it to. My information is 3rd hand, but I have heard that the entire housing is different for a digital dash more than once. I find it surprising that a manufacturer would go to such lengths in the era when consolidation to save cost was the prime focus. My guess is that they could have designed the gauges portion into the existing dash housing, but the System Check and Odometer would not fit into the existing dash.

 

I'll have to remember to check into it someday.

I've got a DD 88 GTA project in limbo right now and a couple analog Trans Am housings in storage. At some point I might find the time to get the parts together at the same time to compare - just so that I know for sure !