My 86 Z-28 has gauge problems that I have traced down to the PC board. My Chevy dealer says the part # is discontinued, and I checked www.gmpartsdirect.com. The part # is 25081605. This PC is what i feel too damaged to repair, and I tried a completely differant dash from an 85 Z-28 auto (my 86 is a T-5), the temp gauge and turn signal indicators didn't work. This is my first posting and I think this is a great site. Any info is greatly appreciated.

 

Welcome to the board.
If the part has been discontinued, then I think your best bet may be to either try the junkyards, or try to repair one of the ones that you have.
It don't think it matters whether its an auto or a stick, but I could be wrong. I have a t-5 and put a cluster in from an auto, but mine is an 84 so i didn't have a shift light.
Did the temp gauge and directionals work befor the PC went bad? Are the directionals working on the outside of the car at all?
Let us know and I'm sure we can help you out.

 

Originally when I got the car the only problem was when the lights were off the dash was fine. When I would turn the lights on the gauges would bottom out and the tach would go up, and would react to the reostat in the dimmer switch. I traced the problem to the PC. So when I got the 85 dash the turn indicators and temp gauge never worked. I think I've made both PC's bad by taking them in and out.

 

I'm more apt to suspect the connectors at the back of the cluster, than the laminated circuit itself. There's not much to go wrong with it and certainly nothing you can't visually verify. I had a problem with the two lower trim screws cutting the traces that run under the cluster; easily fixed with shorter screws.

Pull the connectors and check the condition and connection of the wires in the back of it. It also helps to clean the contacts. It really sounds like something is crossing somewhere, probably the dash illumination circuit crossing with a tach wire or common ground of some sort.

You can save yourself from damaging the laminated circuit by dropping the steering column whenever you remove the gauge cluster. It's an extra step, but with the growing unavailability of those circuits, it's a good step to insure yours stays "healthy".

 

I had the EXACT same problem in my 89 Iroc. My ground circut had a crack in one of the wires on the pc board. I just used a section of the copper from the shift light and soldered it in place over the crack and it so far works flawlessly.

 

Kudos 2 Jza. Many thanx to you. I cleaned everything. The pc board contact areas, the plug contacts, the gauge studs, basically any contact I could clean. I was suprised how dirty everything was when I did clean everything. It works great!

Again thank you Jza, AaronIROCZ, and racerx004.