Need some help with shorted parking light wire

wjdunham · wjdunham's Garage

I have an issue with my '85 Carrera, I have narrowed it down to a short to ground on the wire (grey/black) leading from the bottom of fuse #4 (left side parking lights) to the rear signal light housing. There are two wires leading from the bottom of the fuse, one to the front headlights, and one to the rear signal light. The one leading to the front is OK. Disconnected the wire from the fuse panel and pulled the plug from the rear bulkhead to isolate the wire and it is showing less than 1 ohm to ground.

I've checked as much as I can near the fuse box and rear engine compartment but can't see where it might be running next to something that could have worn through the coating and shorted to the chassis.

Anyone have idea as to how I might isolate where exactly the short is? This harness is pretty buried as it runs from the front to rear of the car...

Thanks!

Bill

Bob Kontak · Bob Kontak's Garage

I swear my engine lid light wires caused the left side parking light fuse to pop. (they were unattached and touching engine)

That was on an 81. Unplug and see if fuse blows.

I also read where the light itself can short to ground in my searches (in the way back)

timmy2 · timmy2's Garage

Engine lid light plugs in at rear male 6 pin connector. Try unplugging it and Check ohms again.

wjdunham · wjdunham's Garage

Quote:

Originally Posted by timmy2

Engine lid light plugs in at rear male 6 pin connector. Try unplugging it and Check ohms again.

I did pull the 6-pin connector and it's still shorted. I should probably check to see if any of the pins are shorted to each other, I'm pretty sure the issue is between that 6-pin connector and the fuse panel, as I can check the wire right at the panel after pulling it from the fuse block and it's showing 0.3 Ohms to a nearby ground.
Bill

timmy2 · timmy2's Garage

I am talking about the single connector on a short grey wire coming out of the male 6 pin connector. It is the power supply to the hood light. Comes off the running lamp circuit in the 6 pin connector.

Tea Tray · Tea Tray's Garage

Did you remove the bulb? Check the socket? Isn’t the plate light circuit in there too?

timmy2 · timmy2's Garage

Plate lamp is on a different circuit, unplugging the rear male 6 pin takes the bulbs out of the circuit.

wjdunham · wjdunham's Garage

Quote:

Originally Posted by timmy2

I am talking about the single connector on a short grey wire coming out of the male 6 pin connector. It is the power supply to the hood light. Comes off the running lamp circuit in the 6 pin connector.

Ah, no, I have not unplugged that connector. I will give that a try when I have a minute. Another clue could be that my hood light is not working either :-)

I did pull the bulbs and check the copper connection that the bulb makes contact with. When I pulled the 6-pin connector it showed an open circuit so I believe the wiring inside the tail light housing is fine.

Bill

wjdunham · wjdunham's Garage

Quote:

Originally Posted by timmy2

I am talking about the single connector on a short grey wire coming out of the male 6 pin connector. It is the power supply to the hood light. Comes off the running lamp circuit in the 6 pin connector.

Does this connector exist on an '85? I'm not seeing it, might be under/behind the electrical panel?
Bill

wjdunham · wjdunham's Garage

Darn, you guys are good, mystery solved with all your help. Turns out that when I installed the new engine compartment light I reversed the ground and +12V wires. When I had the light hanging in the air it worked fine, but screwed it to the lid the ground side (to which I had my +12V) is meant to make contact with the lid mounts which are ground. Reversed the wires and everything is working fine now. When I installed the light housing a while back I knew it didn't work, but didn't get around to debugging it until now. I also didn't notice that the left side tail lights were out until recently, so didn't make the connection.

NEVER would have thought to look at that light if it weren't for your suggestions, so thanks very much!

Bill

timmy2 · timmy2's Garage

Glad you found it. Not sure about the connector location for the hood light on the ‘85. So far I have stayed away from the ‘84 and newer body harnesses. (Plan on keeping it that way for now as they are full of NLA unique connectors.)