Topic: Dash Wiring Issues

[MBurley127]

Hey All,

I’ve been having some wiring issues with my 79 Trans Am. About a month or so ago I had the car out on a drive and all of the sudden both my dash lights(all of them) and my rpm gauge went out. The speedometer and all other gauges and the wipers still work as well as all the other components, just these two went out. I recently had my dash bezel restored and before I can install it I want to figure out what the issue is. I checked the fuse box and someone had put in an improper fuse, where it should have been a 4A fuse someone had put in a 20A fuse, however, the car was working fine before then. I had replaced all the dash light bulbs too, and after re-checking, those seem fine too. I have very little wiring experience and so I’m pretty stuck on what to do and what went wrong. The car has been parked since then and is in the same condition I left it. Does anyone have any advice? Thanks!

[Wallington]

The tacho itself stopped working? Or just the lights in it? It runs off its own harness and shouldn't affect the other unless something already wrong. Simple checks can be the condition of the gauge cluster circuit board on the back, not cracked or touching areas where it shouldn't. The incorrect fuse may have been hiding an issue or caused problems when it could have simply blown the smaller fuse. The circuit board it where I'd start and look for burnt contacts. There should also be a ground strap from the headlight switch to the cluster corner. Was it the instrument lighting fuse that was wrong? Also check that the tacho power in from the accessory terminal in the centre for Ignition, possibly shared by power windows.