Blowing tail light fuses...need help asap

[85_SS_302_Coupe]

So i had my car out the other night and got stopped for not having any running tail lights. So i look into it and my headlight switch is busted, so i replace it (this is an '85 by the way). So i check the fuses and the #4 fuse which is labeled as the external/instrument cluster fuse is blown so i replace it and bingo, i've got tail lights. So i start the car up and warm it up and turn them back on and the fuse blows. Now, every time i turn the lights on it blows the fuse and i'm totally lost

 

[tiptop]

you have a loose wire, its grounding out and blowing the fuse.

 

[93 LX]

you have a bad socket or a wire is touching the chassis. Remove all the lights in the back and see if it still blows. If it doesnt then its in the front or in the instrument cluster.

 

[85_SS_302_Coupe]

Man i'm retarded when it comes to wiring...where's a good place to start? I'll pull the bulb sockets and put in a fresh fuse and try that, but if that fails do i just start tracing wires or what?

Also if it IS the sockets, then what?


Also i forgot to mention the actual brake lights work when you press the pedel, it's just the running tail lights that you get when you turn on the headlights that don't work. The brake lights continue to work even with the fuse blown.

 

[tiptop]

ya wiring is quite a thing, not really sure how to really go about tracing a bad wire other than use a test light, try and find the wire with no power with the key on, and that wire would probally be your problem.

 

[LiquidGT]

I found this wiring diagram for an '86, it should be the same for your car. If you can read it the brown wire (on an '86 anyway) is the power wire for the lights and the black wires are the grounds. Always check your grounds first, bad grounds are what most elec problems are, or start. I'd first look back in the tail light panel to see if the ground connections on the body are good and tight and wiggle the wires and stuff too. I dont remeber if there is a tail light harness connector back there, check it out too.

If not that then I'd look at all of the running light wires around the car to see if the brown wires are exposed and touching metal and the ground connections. Then look at the headlight switch harness to see if tis burnt, corrosion in all the bulb sockets, or anything that seems 'wrong'.

It might be wise to get a test light to help you, I got a test light from walmart that lights red for ground and green for power (or vice versa). A voltmeter is good too, but you can probably get away with a test light in this situation.


Oh, and the brake lights are on another circuit, so they'll work anyway.

 

[85_SS_302_Coupe]

Well by a stroke of luck i figured this out. For starters, i don't have carpet right now, just bare floor. Well, when i took the carpet out i found a 2 wire harness with a small grey plug (similar to what you find on the seat belt buzzer plug) under the carpet on the driver's side. Anyways, i don't have any clue what this could be for so i just tucked it up under the dash. It had fallen down and was laying on the trans tunnel, and one wire was out of the plug and randomly grounding onto the bare metal.

So the lights are fixed which is awesome. Now, anyone wanna guess what that harness might be for? Power seats maybe?

 

[tiptop]

e-brake???

 

[93 LX]

auto panel light or the lights for the console or ash tray

 

[85_SS_302_Coupe]

auto panel light or the lights for the console or ash tray

Yeah console power would be a good guess. It looks like it's been under the carpet since day 1 and since my car didn't come with a console, that would make sense.