Brake/Running Light/Turn Signal Problems

[LuvNLife]

1985 C10 2wd short bed, 350/350, pretty much stock and undamaged, just showing it's age.

I've got no rear lights at all - no running lights, no tail lights, no brake lights and no turn signals. Headlights and turn signals up front work fine.

My question is, could this all be fuse related? I found a simple diagram of the fuse block, and all I'm seeing is "TL CTSY" related to the rear lights. It's miserable outside right now, so I haven't pulled the fuse yet.

Thoughts and suggestions would be appreciated...

[kwmech]

Check the harness plugs

[Dead Parrot]

If the truck has any trailer plugs, check those connections. Those crimp splice things can corrode on the inside and still look fine on the outside.

Also check taillight grounds. Road spray goes up there and after 35 years, possible the ground holes for the screws have rusted away.

Possible a mouse or other rodent did some chewing.

I don't think any of the fuses are divided into front/rear protection zones.

[dmack91]

Not sure on squares, but many older model vehicles had the dash lights on the same fuse as the taillights. Otherwise, the previous posts cover things pretty well.

[Bloodhound]

Follow the rear harness up to where it plugs into the front harness. Check that it is connected there and check the voltage at the plug.

[LuvNLife]

Thanks for the replies so far. Worst part is, I have no idea when they quit working. The truck is a work in progress, and I'd found the grounds were missing under the hood - I had one from the battery to the frame, and even that one hadn't been wire brushed to clear the paint. Got all new cables and had those put on (I've got a bum hand) and everything else works great. I do know from the bumper it was used to tow, so I'll start back there, assuming they ran trailer wires.

I do know I have a new light switch as of today; when I turned the lights on for the first time last week, the knob and arm came off in my hand.

[cadillac_al]

The tail light ground should be under the left side tail light. Like bloodhound said, unplug the tail lights and check the plug for power.

[65chevysub]

Originally Posted by dmack91

Not sure on squares, but many older model vehicles had the dash lights on the same fuse as the taillights. Otherwise, the previous posts cover things pretty well.

I agree wholeheartedly. I used to have a 65 Suburban and one night my dash lights kept going out. Checked my taillights and they were out as well. Replaced the fuse and everything worked again for awhile then they went out again. Found out my taillights harness kept touching the headers and shorting out.