Hello all,

I've been trolling the board for a few weeks now. I recently picked up my 4th C3 of my lifetime. A 78 with 73k miles and almost all original and well cared for.

I'm trying to track down an electrical gremlin that now has me stumped. When I first got the car, all of the dummy lights were lit, and only half of the guages were working. It also had none of the dash lights working. I pulled the clusters and put in all new (LED) bulbs. I replaced the printed circuit behind the center cluster because it looked like it had been to hell and back, and was broken. This brought back all but one of the guages, and all of the dash lights now light. BUT now the dash lights and guages won't go off. With the key off, and lights off, the dash lights are still on, as well as the parking lights. I inspected the harness, and the connection to the circuit board, and all looks good. There are no loose or frayed wires anywhere behind the dash. I then replaced the headlight switch since this seemed to be the next most logical culprit. Well, they are still on. If I unplug the center cluster harness, they all go off. It's a brand new board from Wilcox so I bought it from a reputable seller.

Does anyone have any suggestions on where to check next ?

 

thats interesting.....i would start to see if there is any evidence that some one has spliced into the electrical system wires....for what we never know.....but perhaps there is a non original wire spliced into the system providing power all the time

 

I found 2. 1 was connected to the radio from the light under the shifter plate that appeared to be the "illumination" connection to the radio so that it would dim when the lights were turned on. Although this shouldn't matter, I disconnected it anyway. The 2nd was tapped into the wire on the headlight switch that is only hot when the lights are on, and it was connected to nothing. It was capped of behind the cluster and taped. I removed it regardless. I still have the same problem. Parking lights/dash lights/warning buzzer won't go off. Everything else in the dash appears to be original wiring. I disconnected the battery for now until I can start working on this again tomorrow.

 

Disconnect the light switch, see if the lights are even being powered that rout.

 

Will do. I'll try that first thing in the morning and will advise.

 

OK, sometimes a good nights sleep and a fresh set of eyes can do wonders. This morning I unplugged the new headlight switch and reconnected the battery. The problem was still there so I started tearing the center cluster apart again. I unplugged the center harness and the problem was gone. I took the old printed circuit and carefully compared it to the new and found them identical. Sooo........ leaving the headlight switch unplugged I took a tester to the center cluster plug and found current in only 1 wire. It was the orange wire which my diagram says is the clock ---- makes sense. So I traced the conduit on the circuit board and it all made sense. I looked at the lugs on every terminal and found that the nut on the one on the clock was different. I know I put them all back on the exact places I took them off from, but the nut on the clock terminal was just big enough that it overlapped the positive conduit on the board and was sending current back though the board and all the parking lights, guage lights, etc. As soon as I put a new nut on it, the problem was solved.

Thank you for the input on this !

 

Cool