I just finished a complete digital dash conversion on my 89 GTA, there are already some detailed How To posts by others so I thought I would just share some of the issues I encountered when installing. I have posted my intro post here:

https://www.thirdgen.org/forums/memb...hased-gta.html

First off – items required:

· A good volt meter
· Service manuals (or the wiring diagrams) for both the digital dash and for the year of your own vehicle
· Soldering iron, solder, electrical tape
· Wire splice connectors
· Band aids (lots of sharp edges)

Digital Dash Components required:

· Dash Assembly
· Dash Carrier (the donor was an 88 which is the same carrier for the 89 as it already had the cutouts for the digital connectors)
· Under dash harness
· Head light harness
· Tail light harness
· Power door/mirror harness
· Door ajar switches
· Radiator from an 87 or 88 that has the hole for the coolant level sensor
· Coolant level sensor
· Washer fluid sensor
· NC SPDT push button (for Hatch Ajar explained below)
· Digital heater controls (optional – I couldn’t source all the components, so I left in the analog controls)

The first item I tackled was the tail light harness. The donor harness came from an 88 – most of the wiring was the same but I had to rewire the following:

· The power source to the light in the hatch area is wired differently, I used my existing connector and soldered the power for this light to my connector. On my car the power splits from the light and feeds the motor – I didn’t see any provision in the donor harness for this so a simple mod make it work.
· Hatch release – this wire was missing from the donor harness, so I had to run a new wire from the hatch release relay to the back to control the hatch release.
· The harness has a 3 pin connector for the DIC, 2 I believe were for the lights monitoring and the orange wire is for the hatch ajar warning in the DIC. From previous posts I learned that the orange wire when grounded sets off the light in the DIC so I bought a “normally closed” pushbutton which when un-pressed (hatch up) would complete the circuit and set off the warning light in the DIC. With the hatch closed, the circuit would open thus turning off the warning light. Picture below of where I installed the switch (one lead connected to the orange wire of the DIC, the second to ground). It works – but I have to get a larger button as it was not high enough to make contact with the hatch when closed. For now, I put a felt pad directly above the switch (underside of the hatch) which makes contact with the switch and closes it.



· Since everything was open, I installed a backup camera and taped the wiring for the camera to the harness to keep it neat.

Second item tackled was the door/power mirror harness. The wiring for the door ajar can easily be separated from the harness – I did this, so I didn’t have to remove my existing harness. Cehbra’s post explains how to install and the wiring so I wont go in to the details but it was pretty easy to install.

The third item was to start removing the panels from my dash and label all of the connectors. I took my time with this (over 3 evenings) properly identifying all connections then going to the digital dash harness and finding the same connector to label it (to make installation easier).










For the most part, the connectors are the same – differences below:

· My 89 has the VATS security, the donor harness had no provision for this. The VATS system consists of the VATS module (behind the dash carrier on the vent), two orange wires at the steering column for key resistance, and the starter enable relay (located at the driver’s side kick panel). I ordered the VATS bypass module from HAWKs which sends the signal to the ECM to enable the injectors. I wired this first to make sure I wouldn’t have any problems once I swapped the harnesses. It worked!
· The harness from the 88 (donor) had a separate fuse box which provided power to the power door locks, power mirrors and windows – consisted of 3 wires (pink and two orange/black wires). I was able to located the same wires on my harness (drivers side kick panel) but they were in a 3 pin connector (no fuse box). I cut off the connector on my harness and soldered it to the same 3 wires from the donor dash and eliminated the fuse box.
· The donor harness had provision for gain control/subwoofer which I didn’t need so I just taped up those connectors (I think there were a total of 3) to the harness.
· I was not able to source all the components required for the digital HVAC controls, so I decided to leave my analog controls. The digital dash harness has a total of 6 connectors for the digital HVAC controls. Two go to the control unit itself, two I believe went to the heater box, and there were two additional ones located near the passenger side which went to AC controls. The analog controls uses 3 wires, one for power and the other two for the dimming lights that come on and light up the controls when the lights switch is turned on. I was able to trace the wire from the fuse back to the connector on the donor harness (brown wire) and isolated it – and soldered the connector from my harness on to it making it plug and play. For the dimming input, I just spliced in to the shift indicator light which was the closest source. Rest of the connectors on the donor harness were taped up and tucked away.

My car has the steering wheel audio controls, the donor dash had the provision for this as well – it’s a two-pin connector with orange and black/blue wires. For some reason I can not get the controls to work with the new head unit (I don’t know if they worked when I bought the car as the previous owner had already removed the original stereo). I know I am supposed to get around 4.2-4.7V on the orange wire which should fluctuate when a steering wheel button is pressed. In my case, when I press a button, I get an out of range (or short) on the volt meter. Any way – something I will need to tackle in the future!

The dash went in easy – took only 5 minutes with the help of my daughter and reconnected all the connectors took another 10 minutes – labeling everything made is so much easier.

So….I reconnected the battery to see if everything worked or went up in smoke, to my surprise the dash lit up however the section which displays the odometer was flashing 999999. I had already ordered a new chip from Cehbra with the my correct mileage just hadn’t arrived when I finished the dash assembly. So while I was waiting for the chip to arrive I tackled the fourth item which was the head light harness. Pretty much plug and play, the donor harness has an extra connector for the DIC which needs to be brought in to the car though the firewall. The only other difference was where the fog light relay was located. On my 89 it was located close to the firewall just behind the washer fluid bottle, in the 88 it’s located around the battery.





The headlight harness has two additional connectors – one for the washer fluid low signal, the second for the low coolant. I had already replaced my radiator with a new one from rockauto – I knew I was going to attempt this swap so I ordered one for an 88 which has the slot to insert the sensor (sensor also purchased from rockauto). I still have not received my washer fluid sensor – only item not connected at the moment. Also, realized that the right door ajar switch does not work – should have checked before installing it! Anyway, the switch is available for purchase.

The Chip arrived from Cehbra and everything lights up as it should, so I reinstalled all of the panels and cleaned up!





At the same time of the conversion, I ended up installed keyless entry/hatch release and installed and 8” touch screen stereo (Joying). Its actually a single din unit that has a detachable screen. I ordered the flush mount Metra kit and it fit perfectly.






There is a lot of information on this forum – which helped immensely so thanks to all who contribute to the forum.

 

Very nice and well done!
Good to see that the digital dash still gets attention!

 

Thanks Cehbra!

The 80's tech is so fitting for these cars...not sure why GM stopped installing the digital dash 89 on-wards.

 

Pretty cool, is this a canada dash? Metric oil pressure and coolant gauge. Never seen this in person.

 

Yes, it's a Canadian dash - you need to take a trip out to Canada and have a look!

 

Well, that would be a 6000 kilometers trip one way.

 

Very nice work, it looks fantastic. Hopefully my 88 GTA Will be looking as good soon. I too have messaged Cehbra as I am in need of a chip as well. Hopefully he has one left for me

 

So glad I just bought a whole car for a 1 to 1 swap. Gonna be super easy. Now if I can just find a way to make the leds work for the front lights without throwing a indication that would be solid.