Strange tail light problem.

[evilunclegrimace]

Well I lost my brake lights and rear marker lights today. The odd thing is that when I turn my headlights off the rear lights come on and stay on even if the truck is turned off. I do have turn signals front and rear. I did a little diagnosing and I think I found the problem. Any body want to guess what the problem is. I will know in the AM when i can pick up the part and install it.

 

[skylark]

You smoked the headlight switch and its connector?

 

[evilunclegrimace]

You smoked the headlight switch and its connector?

Nope! That was my first thought.

 

[PeteyG708]

Nope! That was my first thought.

Circuit board(s) in the taillamps?

 

[CrustyJunker]

Also curious what you find. My old Tahoe's tail lights would come on randomly and stay on while it was parked, but no parking lights and it wasn't the brake lights or brake switch. To make it worse, the horn was also involved, along with the left turn signal. I have a video of it somewhere... Was pretty sure I was gonna have to set my truck on fire.

 

[evilunclegrimace]

Well i followed the diagnostic chart in the factory wiring harness manual and it pointed to a bad turn signal switch. When i plugged it in to the circuit there was no change so i put the truck in the garage with the heat turned up to melt all the snow off (we received 65 plus inches since the 25th.)

After the truck dried off i was able to get under neath and inspect the wiring harness i found that the ground at the rear of the truck had pulled loose from all of the snow. Once i fixed the ground the lights returned to normal operation.

 

[CrustyJunker]

Cool, thanks for coming back and sharing!