We have all seen those cars with wiring nightmares from previous owners and having a car plagued with gremlins. I knew this car had quite abit of 'questionable' things intalled in its life span..and I added a ton of stuff after that. Now the car with its age is starting to fight back and things work or dont as they wish and I finally had it. I broke down and said its time to gut this fish and fix everything I could and put fresh wire where it needed. Ive never taken a 3rdgen dash fully out before and dont know why i thought it would be more difficult than it was. Taking the dash out isnt hard..but what made it hard was all the wires looped..patched..lengthened too much and or cut too short in or around parts of the dash..bare wires cut and dangling. Just a total mess! Now I admit some of it is definitely my fault too when we swapped everything from my previous t/a to this car in a weekend from 305carbed/auto to lq4/t56 with a very tight time frame the goal was to drive the car backout on a monday morning and we started the friday evening. So yes..things werent done to the best of my abilities with that stuff..but it was functional..soldered etc.

I was amazed at all the stuff i found taking the dash apart and adding to my list of what does this wire do and everything I need is still working lol. I wanted to take you guys through the journey as I fix this pile and address other concerns about my firewall flexing at the clutch pedal and find out where i have a massive gush of air on the passenger side near the heater box.

Heres day 1 of the madness and you can see my pain. But I promise the end of this wont look anything how it started! Wish me luck.

 

What's funny is I was JUST looking for dash posts because I have been re-doing the ENTIRE interior on my 1991 Firebird and had the interior completely stripped. I pulled the dash and had to disassemble it as it was half hanging there to get that main dash wiring harness off the dash to remove it. The problem is now to go back in, you have to have the main harness run in between the dash frame and the front of the HVAC box that is attached to the dash frame but the main harness doesn't have any connectors to disconnect it from the rest of the body harness!

I'm a professional technician and I have been since 2000. Almost everything I have worked on (Mostly GM and Mopar products) have big main connectors where you can keep a lot of the dash assembly intact with the dash wiring, disconnect the dash wiring from the rest of the body, and then remove the entire dash and disassemble it more on a bench if you need to and access the wiring. They aren't too bad. But 3rdgens are a MAJOR PITA!!!! You can't get all the wiring in where it is supposed to go between the dash frame and the HVAC box while assembling the HVAC box to the dash frame with it all hanging there. I tried and ended up breaking one of the main tabs on the dash frame and then had to take the while thing out, plastic weld that tab with reinforcing steel mesh and put it back in.

I ended up cutting the right side rear speaker wire and will later add bullet style connectors so I could detach the right side of the harness and snake the whole thing THROUGH the dash with all the HVAC ducting connected to the dash leaving all the bottom screws off so I could separate the frame from the HVAC box enough to make room for all the large connectors on the wire harness. It worked, but my hands look like I got in a fight with a Bobcat. I have huge bear paws so maybe a more slender man would have an easier time... Luckily i did this before putting the seats back in so i was able to lay down on the floor while I did this.

I am REALLY considering cutting the dash harness from the part of the body harness that goes rearward and installing a large multi pin connector from a leftover damaged harness we usually keep around to pirate stuff from at work. Unfortunately, we always replace only one side of a harness so I don't have any big connectors that are both the male AND the female side. I will probably end up buying one of those dash connectors new from our parts department with my employee discount and doing it that way...

But yes, these are the worst dashes i have EVER worked on in my 22 years as a dealership technician.

 

Lol aww man the dash wasnt that bad to take out for me. I agree the main harness from left to right could use a main plug to disconnect but it didnt really hinder me getting the dash out once I knew what needed to stay attached to the dash or not. I also undid every screw. So once i unbolted the column and started pulling it all forward..the main hvac ducting dropped and i had room to move the harness completely away from the passenger side down and away from the dash. Then it came out with no fuss. I took pics step by step as a reminder of which order things came out to go back in reverse. Putting it back together was harder because i moved alot of wires and added alot of wires for the alarm etc whilst hiding it all aswell made it a tight fit.

 

3rd gen dash is like Legos, you put it together one piece at a time. If you try to do things modular then you're screwed.

When I first read your post I thought to myself, what's the big deal, I've done this five or more times. Then I remembered the first time..... With my Firebird I got rid of all the rivets that hold the big plastic shell to the metal rail. Being able to separate those two things helps a lot. Lets you work behind the dash without removing the rail and harness. I use bolts, nuts, washers where the rivets used to be.

 

Lol absolutely right, if I had to do it again now it would be a breeze to remove and put back. But I also had a nasty pile of wiring to sort out and make sure it would go back without interference with the dash as I tucked some parts and added others. But slowly i made progress and with that I took time to do other tweaks before I fully put this thing together. I dropped the headliner to fix it and add a blazer overhead console and make it work. New alarm/starter with some aux functions and then its tedious things you forget..fixing clips..missing screws/bolts etc. Heres the progress so far:

 

I got the dash all back together,no more rattles.flickering lights/gauges. New alarm hidden install,new arm switch for the 2step,new steering wheel put in..overconsole looks great and super bright with the leds.It was alot more work then I expected but worth it. I also ran 1awg power and ground wire to the battery in the trunk,the old stuff was oxidized pretty bad and had bad voltage drop. The car electrical is much happier..voltage is steady 14.2 at idle and hits 15 while driving.

With the dash done and moving onto doing body work and wrapping the car. I also took on another project vehicle with the shop owner.In the background building a 86 sierra 1500 single cab long box. Lq4 with ported heads 4l80e and decided to put an lsa on it a few wek ago.Full frame off restomod. I made my 1st complete base tune and test fired it up on some brake clean...wow

Enjoy