911 SC taillight problem.

[hdrockerroller]

So my left taillight is out.
I went to replace the bulb and the bulb was still good, new bulb didn't work either.
Started trying to track it down. Fuse #4 was blown. Ah that's go to be it.
Replaced the fuse. Still no taillight. Fuse gets very hot with headlights turned on.
Cleaned the taillight ground, still no taillight.

With the fuse getting so warm, I'm assuming short somewhere.
Is there any usual place these short out?
Any tips to narrow down the search?

All input greatly appreciated, I need to get it inspected and am dead in the water till I can get this silly taillight sorted out.
Thanks
Paul

[911truther]

remove the light assembly and open it up .... mine had old build up of debris which gummed up the slide contacts ....one of the brake lights would was 50/50 on working .... drilled out the socket and installed an off the shelf plug in .... got it lite up and never looked back.... new gaskets from our host and I am done with that issue good luck

[pete3799]

Also clean both sides of the fuse holder. A Dremmel with a wire wheel works great for this
( disconnect the battery first).

[Dpmulvan]

You might have to drill out the screws.

[hdrockerroller]

Ok, unplugged the taillight assembly from the wiring harness from the plug that's inside the engine compartment on the back side of the fender well. If I turn the headlights on, the front parking light comes on, but fuse #4 still gets so hot it will burn your finger. If you leave them on very long the fuse blows. So somewhere there must be a nearly a dead short. Or something. Is there any usual places that the taillight harness shorts out? Anyone know where these wires run? Do they run through the tunnel? Any other suggestions on how to track this down? Thanks

[timmy2]

Fuse 4 feeds both front and rear marker lamps. The problem may be in the front. (Due to overheated fuse CLUE with rear tail light harness unplugged)
Might be drawing down all the Voltage so none goes to the back!

Lift the wires on the bottom of the fuse. Pull the front lamp as well.
Then use an ohmmeter to see if one wire has a very low resistance to ground.

The wire to the rear lamp is part of the through body harness.
The one to the running lamp up front goes through the front harness and makes a connection in the headlight bucket, then to the marker lamp.

[hdrockerroller]

Thanks for the suggestions. I will see if I can trace it down.

[hdrockerroller]

OK, I pulled out the front bulb. Rear taillight is still unplugged from harness. Turn on headlight, fuse still gets very hot fast. I pulled the fuse and ohmed out wire from top of fuse, and no path to ground.
Ohmed out wire at bottom of fuse (with meter set at 200) and there seems to be a path to ground. (ohm meter went to zero) But the weird thing is, if I ohm other fuses to ground they also go to zero. The hot fuse tells me there's a short, but the ohm meter reading on the other fuses is confusing. Going to pull the headlight next and see if I can find the connection to the front light.

It just seems that if there were a dead short it would blow the fuse instantly instead of after 10 minutes.

[timmy2]

Both wires on bottom of fuse measured low resistance to ground, or just one of them?
Top wire normally comes from light switch. 2 bottom wires go to front or back of car respectively.

Don't worry about other circuits nearby, they have paths to ground through their end devices.

[hdrockerroller]

Pulled out the left headlight assembly. Looks pretty clean, wires look OK.
There is one female spade connector that was not connected to anything, but it was taped so it wasn't shorting. It has two wires going to it, one went to the headlight harness coming into the headlight bucket on the far right side of the car, the other wire goes to one of the connectors on the head light plug/socket.
Is this connector supposed to be a ground?

[hdrockerroller]

timmy2, I didn't disconnect the wire's that go to the fuse yet.
I'll do that next and retest the continuity of each wire separately.

[timmy2]

Look for same grey/red or grey/black as at fuse 4 in headlight bucket.
It should be to a plastic rectangular connector.

[timmy2]

Pm me your phone number and I'll call you if you like.

[hdrockerroller]

The bottom of fuse #4 has a black-n-white wire and a brown wire.
The black and white wire ohms out at 8.5 with meter set to 200.
The brown wire ohms out at .5 with meters set to 200.
(Rear taillight is still unplugged)

timmy2: Thanks for all the help! I'll see if I can figure out how to PM on this forum.

[timmy2]

Pm is simple. Just highlight my username and select private message.
Brown wire in fuse 4 doesn't sound right.

[timmy2]

Good chatting and testing remotely with you Paul.

Now you have the grey/black from fuse 4 running through the body harness to the 6 pin connector isolated as the problem wire that is shorting to ground.

Dig in and look for abrasion points or pinch points at both the front and rear fuse panels on that wire.

Keep us posted.

[hdrockerroller]

timmy2: Thanks for your help on the phone.
I verified that I can hook the front circuit back up (leaving grey/black wire that goes to the rear disconnected) and the front lights work without blowing the fuse.

I pulled up the wire going to the rear in the trunk of the car as much as I could and traced it back to a point it goes into the harness and didn't see any place it might be in trouble.

But in the engine compartment, the harness going to the taillight connector appears to be stuck underneath the aluminum relay holder that holds the blower relay, and defogger relay. I'm hoping this might be the issue, maybe it wore through the harness and shorted the wire for the taillight.

I'm getting ready to take that all out and see. Just had to come in and cool off for a minute. I'm in texas and its hot in the garage.

Thanks again for you help, timmy2.

[timmy2]

What, no A/C in your garage?
What is this world coming to!

Sounds like you may have a good location to continue the search.
Good luck and let us know what you find once you are cool.

[hdrockerroller]

Well I pulled up all the stuff covering the harness on the left side of engine compartment and went over every inch of the wires. There are no visible shorts within the engine compartment. I did have to move a family of mice out this car at one point, so its possible they chewed through a wire, even in the tunnel.

Dreading the thought of trying to pull a new wire all the way from the front of the car, through the tunnel to get to the 6 pin tail light connector.

I'm considering two different temporary measures until I get time off and can fix it right.
1. Fuse #2 is the license plate light. I could splice into that grey wire in the engine compartment and run that wire into pin #4 on the tail light harness, cutting the shorted wire off.

2. Splice into the wire on pin #4 of tail light connector on the right side of the engine compartment and run a wire into pin #4 of the tail light connector on the left side of the engine compartment, cutting the shorted wire. Both tail lights would be fused by fuse #3 instead of fuse 3 and 4.


timmy2: Any idea where the grey wire for the license plate light comes out in the engine compartment? Is it one of the grey wires that are also in the 6 pin taillight connector?
Either of these ideas sound worse than the other? They are both kinda ugly, but can easily be undone when I get the time to pull a new wire and fix it right.

[timmy2]

Grey for license plate lights would be an easy one to splice into to feed the running light. It is the grey wire to the 6 pin connector pin 1 as per clockwise starting from locator key.

One other thing to check first.
Is there anything plugged into the rectangular connector on the short grey wire coming out of the male 6 pin plug? If so, unplug it and test the original circuit to ground again...
That is for the engine lid light and could be the root of your problem if installed.