Hello all. I have a 1994 Corvette. My issue started after replacing my heater core. Under the dash on the passenger side are two sets of wire connecters that apparently can be plugged into each other. Upon reassembly, I apparently got them switched and caused something to blow. The car would not start. I diagnosed the problem as a faulty ECM and had the ECM repaired. After the repair, the car started and ran fine, but my digital dash did not work correctly. All of the analog gauges work, and the digital fuel level works as well. But the speedometer only reads as zero, and none of the digital temperature displays work either.

I suspected the ECM was still at fault, so I sent it to a different vendor to be repaired. They sent it back saying that it was damaged but they could not repair it. I decided at that point that since I needed a new ECM I would install a Torqhead 24X system, since I was contemplating that anyway. I installed the Torqhead setup, and the car runs and drives fine with it, but I still have no functionality of my digital gages.

Since nothing changed with the Torqhead install, I'm thinking I may have damaged a relay or have a short somewhere. I do have both red factory service manuals and am attempting to diagnose the problem using them, but electrical work is not my forte. I'm hoping the experts on here could maybe give me some ideas on things to check.

Thanks!

 

The CCM controls the dash. I would get the instrument panel checked first to see if that is functioning properly. You have to many unknowns.
I would send it to Batee.

 

I have been chasing this issue on and off for the last four years. I finally got it figured out this weekend. Turns out that there was another set of connectors that were plugged in incorrectly. I've been chasing an electrical issue caused by my own lack of attention to detail. I think I was so happy to have the heater core in that I rushed the re-assembly and caused myself all kinds of issues. Moral of the story, just because two plugs fit together, does not mean that they do go together.

 

Good job resolving the problem.
As we say in engineering, configuration is everything. In electronics for over 50 years and I always label everything, now you will.