Eric Briden

How's it going gents, first time poster on this site. I've done some research on this and I'm still stumped.

The issue started out as this, tail light fuse kept popping, rendering the tail lights and dashlights to go out, obviously. Turned out it was from improper radio installation from the previous owner. Fixed it, worked well when in the driveway, on the way to work the next morning, tail light fuse pops.

So today I disconnected the trailer harness and guess what?! No more fuse pops! But..... now, no matter what, the dash lights and backup lights stay on no matter what until the fuse is pulled. Brake lights don't even work. I'm not big on electrical issues but I can hold my own until I run out of ideas.

1980 Toyota.

Thanks in advance boys.

rowdy235

My only thought is something is still messed up back there with the trailer wiring, somehow feeding 12v to both the backup lights and tail lights (dash lights).I have a wiring schematic for an 82 which should be similar to your 80, and it doesn't look like there is any common bond between the reverse lights and dash/tail lights other than the light itself is combined. The reverse lights get their power from the "heater gauge" fuse and go through the switch on the transmission. Obviously the taillights get their power from the tail fuse.

A Couple questions-
Have you removed all the traces of the trailer wiring?
Does anything change if you shift the truck into reverse? Turn on the taillights?
Are only the dash lights on or do the taillights and running lights run as well?

Honestly from what you've described the problem points back to the trailer wiring. I'd probably look over that and make sure everything looks okay. If anything doesn't look factory, investigate it.

Eric Briden

I clipped the wires to the trailer harness and put a "bandage" over the wires where they were spliced together for a temp fix on that until I can get this figured out.

No brake or reverse what so ever. The tail lights and dash lights controlled by the tail light fuse stay on no matter what until fuse is pulled.

next option, rewire everything.

rowdy235

Per my schematic the backup lights are not powered by the tail fuse, so it seems to be there must be a short letting the taillights back feed the backup light circuit. The fact you have no tail or brake lights further points to a wiring issue.

I hate to say it but it may be time to dig into the wiring

rowdy235

Also does your headlight switch work? do the headlights work? Seems odd the lights won't turn off.

Eric Briden

I just finished pulling the harness from the cab to the tail lights. Found one discrepancy on a green wire with a white stripe that I'll fix, insulation had rubbed through. Whoever had installed the trailer harness butchered the oe harness..so I patched all that back together. I'm going to plug it back in and see what happens.

Headlights turn on and off and brights work. So it can't be the switch, can it?

Eric Briden

Ended up rewiring the bastard and throwing a switch in on the tail light circuit. sent a new wire from the stop fuse to the harness where it begins at the back of the cab. to hell with tracking down a short in someones cluster of a wire massacre. I ought to find the kid who owned this rig before me and make him undo what he did.

dropzone

iTrader: (6)

so when you put this bandage over the clipped wires did you tape them individually or just wad them together? you could be shorting in that wad of wires.

you need to start sorting the wiring using a test light or meter, tag as you go