I've spent the past couple hours doing a search on the digital dash gremlins that effect early C4's and before I lose my mind trying to decipher schematics and wiring diagrams I'd like to get some input into what may be causing my display to suddenly stop working. Last night when I took my 86 out for an evening cruise, the dislpay was black. Turn signals work and when I turned the right turn signal on the display went nuts for a few seconds and went black again. I've read that quite often it's a bad ground wire and that the ground is somewhere on the driver's side door sill. Any pictures of exact location and what I'm supposed to be looking for would be appreciated.
It's funny my display has always worked like new and I was wondering if condensation or extremely high humidity could effect it as the weather has been unbearably hot and humid in PA.
I hate to have to think I'm going to have to remove the cluster and send it out for repair. It's not just the money, but I'd be without the car in prime summertime driving season. I'm not keen on trying to solder or rewire as I don't have the tools or skills to try repairing myself.
Any helpful hints would be appreciated.

 

A common issue is related to the Ambient Temp. Override Switch. This switch is located at upper RH corner of the bulkhead connector under the LH hush panel. Unplug the 2-wire connector to this switch and jumper the two pins of the connector and see if the display comes on.

The main display ground is located at the door hinge A pillar.

You could try pulling the cluster and cleaning the PC board connectors.

 

I have a used one for $200
Has 55k on it
automobiletest.com/parts/used/Corvette/1986/index.htm

 

Pardon my ignorance but I'm not sure what the "hush panel" is or where it is for that matter. Also when you say jumper the two pins do you mean like using a paper clip? Sorry for my lack of automotive knowledge and thanks for your help.

 

The hush panel is the carpeted panel under the dash below the steering wheel. There are three screws up front and one clip on a bolt at the bottom rear center.

Yes, just jumper the pins with a small paper clip will elimiante that Temp. Sensor from the circuit.

 

The hush panel is the big plastic panel directly over your feet. It covers the lower half of the steering column. And yes, he means jumping with a paper clip. Good luck.

 

So the ambient temp sensor can cause the entire dash to go black? Mine is completely dark 95% of the time, but sometimes one or two of the four backlights works. Could this have anything to do with the sensor or is it more likely a ground problem? Thanks

 

Know what you mean, I to had something similar to yours, mine in an 84 would go blank when I gave the gas to it, very strange, but I checked the grounds and the ambient switch to, they all checked out fine, I finally sent it out to be repaired, it works fine now. but I didn't want to get stuck again with no dash so I bought a spare one just in case, Haven't needed it yet but it's there. good luck

 

on the clip under the dash what pins do i jump
sorry i dont know to much about electronics and dont want to go out and spend the money if its not the dash
thanks guys
lost?