tail light harness?
10-03-09, 02:00 PM
#1
tail light harness?
What does the original tail light harness look like? I'm having severe problems with my tail light fuse blowing. The harness I have is cut up at the rear end and spliced. It is a black bundle resmbling what you'd see inside a computer. Flat and all wires are black. It blows with the switch on or off. As soon as I put a new fuse in the clips it glows red and pops. What would cause this? A short is what I assume is the problem. It looks like my tail light harness was modified by a previous owner for some trailer lights. The car has worked great for over a year until last night. All I did yesterday was adjust the alternator tension and adjust the brake light switch on the brake pedal. Then I'm driving down the road only moments from starting the car and the interior lights all go out and my taillights stop shining. Brake lights work and blinkers blink, but do not stay lit as markers. Headlights go up, but they don't go down.
When I stick a phillips head in the fuse socket to jumper the circuit the lights and motors and radio all work. (I only did it for a quick second because I didn't want to melt anything).
I get 12v from the chasis to the hot side of the tail light fuse prong (big wire).
I noticed a couple weeks ago my light motors started slipping and twitching. Could there be a short in the motors and they still work?
When I stick a phillips head in the fuse socket to jumper the circuit the lights and motors and radio all work. (I only did it for a quick second because I didn't want to melt anything).
I get 12v from the chasis to the hot side of the tail light fuse prong (big wire).
I noticed a couple weeks ago my light motors started slipping and twitching. Could there be a short in the motors and they still work?
10-04-09, 02:48 AM
#2
Not much of an electrical expert-
-have you tried checking and re-soldering the previous owners wire mods?
-is there somewhere along the harness where a wire has frayed and is grounding out?
FWIW the entire rear harness is a separate piece and can be swapped out. Plugs in up just under dash on driver side. Lots of folks parting out 79 or 80 SAs, should be able to get a whole rr harness for $25. Might be your easiest solution, assuming that's where the prob lies.
'Luck
Stu Aull
80GS
Alaska
-have you tried checking and re-soldering the previous owners wire mods?
-is there somewhere along the harness where a wire has frayed and is grounding out?
FWIW the entire rear harness is a separate piece and can be swapped out. Plugs in up just under dash on driver side. Lots of folks parting out 79 or 80 SAs, should be able to get a whole rr harness for $25. Might be your easiest solution, assuming that's where the prob lies.
'Luck
Stu Aull
80GS
Alaska
10-04-09, 06:31 PM
#3
If you messed with the brake light switch I'd start there. Maybe you bent something or now something is touching that shouldn't be... but then again just thinking out loud with no knowledge of how the brake light switch works... The brake light switch is just a switch and should only interupt or continue power. I don't see how it could short unless something ground is touching any contact area of power, ex where it hooks up or is adjusted...?
There is a big plug that connects the whole rear harness to the front harness located under the drivers side bin. Pull the bin and unplug the harness and at least you can tell from there if the short is up front or in the rear. If the fuse still pops with the plug disconnected you know the short is up front and not in the rear where the previous owner wired in the trailer.
There is a big plug that connects the whole rear harness to the front harness located under the drivers side bin. Pull the bin and unplug the harness and at least you can tell from there if the short is up front or in the rear. If the fuse still pops with the plug disconnected you know the short is up front and not in the rear where the previous owner wired in the trailer.
10-04-09, 09:17 PM
#4
That's what I was gong to do, but I popped my last fuse, doh!
I'm just going to lay new wiring down from scratch. The factory setup has the tails and markers come on as running lights anyway so I'm just going to start a new circuit just for them, splice up to the cluster dimmer switch/ dash lights, and run a relay off of the defrost circuit since it only comes on when the key is in the ON position) to open up 12v battery power straight to the lights. Sound good?
Then I'll just have to figure something out for the headlight motors to go down. Where is the device located that controls the DOWN action of the headlight motors? Maybe I can rewire it into the up/down switch in the dash from scratch like it was a fog light circuit. If I do that will the lights continuously go up and down up and down on a loop? Or just up or down once and stop until I push the switch again?
I'm just going to lay new wiring down from scratch. The factory setup has the tails and markers come on as running lights anyway so I'm just going to start a new circuit just for them, splice up to the cluster dimmer switch/ dash lights, and run a relay off of the defrost circuit since it only comes on when the key is in the ON position) to open up 12v battery power straight to the lights. Sound good?
Then I'll just have to figure something out for the headlight motors to go down. Where is the device located that controls the DOWN action of the headlight motors? Maybe I can rewire it into the up/down switch in the dash from scratch like it was a fog light circuit. If I do that will the lights continuously go up and down up and down on a loop? Or just up or down once and stop until I push the switch again?
10-04-09, 09:22 PM
#5
I took the harness out of the car for inspection a couple days ago and it looks decent. I'm thinking the problem is between the fuse box and the switch or on the front side of the harness (going to the front markers and motors).
