No taillights!

[gt1009]

When I turn on my headlights, the taillights don't come on. Also, the turn signals don't flash they just stay on. I honestly have no idea what the problem here is. Please help me out.

[5speedsilverado]

have you done any upgrades to the truck? also what year is it and what model?

[gt1009]

Wow that was possibly the worst post I have ever made. No recent upgrades to the truck, and nothing that would have messed with the electrical system. It is a 90 k1500.

[99'HEARTBEAT]

I would take a look at the fuse for the taillights??

[2ToNe04]

check your fuses

[vncj96]

It is possible to put your lights in the wrong way on some cars

[Crakums_GT]

Sounds like something in your fuses. Possibly the flasher for the blinkers.

-Greg

[tattooed4life]

Does it have a third brake light? If it does, does that light up when the brakes are applied? If so, then it is probably the turn signal assembly on the column. All of the wires and controls for the turn signals and the brake lights run thru it. They just wear out and fail after years of use.

[bill190]

Check fuses first of course. Your owner's manual will give fuse information.

If fuses ok, unplug the electrical connector to the rear taillights which is under the rear of the vehicle. Check the connector for tail light voltage and the other rear light signals.

If you can't figure out the wiring, probably best to get a GM Factory Service Manual set for your year/model vehicle. (Order from helminc.com of a GM dealer.) I think that year has a separate electrical diagrams manual to the set. Anyway this would give detailed troubleshooting instructions.

Then if power is not present at the rear electrical connector, check the electrical harness all the way up to the front. This runs under the vehicle along the frame.

Especially check towards the front of the vehicle where this harness goes up into the engine compartment and runs up the firewall. You would be looking up at the cable from down under the truck, but there is a sharp metal piece which can cut a small slit into the cable from above where you can't see the cable. So feel the other side of the cable with your hand or look at it with a mirror/flashlight.

If this is the problem, you should have had problems in the past with fuses blowing as this would have grounded out the wiring.

Anyway if not getting power to the rear, check that entire cable going up to the firewall.

If you are getting power to the rear connector, check your rear tail light printed circuit boards. These might need replacing. It would seem odd that both would go out at the same time though.

[2COR517]

I would suspect a short. Sounds like the rear harness is crushed somewhere. The taillight fuse is likely blown, and will probably fry again if you put another in. As someone else stated, unplug the rear harness behind the bumper and see if that fixes it. If not, you can pull the rear harness plug at the firewall and try again.