Tail and reverse lights out

[Jskingry]

Hello again,
1993 K1500 Silverado 5.7l automatic.

So I noticed my tail lights are out. The middle bulb works for turn signal and brake lights but the top and bottom bulbs which appear to be running lights and back up lights are not working.
I tested the plug and no power is getting to the rear for them. All my fuses appear to be working except one that is labeled “park lps” there is a 30 amp fuse in that slot but no power on either side of the fuse.
Any thoughts on trouble shooting this fuse but more importantly the tail lights?
Thanks

 

[Jskingry]

Alright,
Found a broken brown wire on the backside of the headlight switch. That was preventing my running lights from working, I have fixed that now I have running lights in addition to my brake and blinker lights so I can legally drive at night. Only light not working now is backup light, I have good bulbs but am simply not getting juice back there.
All fuses are now working. Anyone know next steps? I assume I start by finding the switch or wire and work back from there. This is especially important because I am wiring a backup camera into the truck.

 

[df2x4]

If you haven't already, check if there's any trailer wiring plugged into your tail light harness in the back under the rear bumper. They're usually on a T connector and if they corrode or get damaged you can have issues like this. If there's anything plugged in back there I'd unplug it and hook the harness back together, then see if your reverse lights start working.

 

[Ando069]

I have this issue on my 88 i did remove the dash switch and (thanks to you guys) i did find a trailer wiring "T" i removed it and reconnected to the original harness... but no luck.. still no Tail Lights.. I do have blinkers working and Brake lights work fine.. all the wiring seems fine off the back of the Switch as well.. I plan on replacing the switch.. and i'll clean up the ground a bit... i'm guessing here but wouldnt the ground also affect the blinkers and brake? who knows.. i'll clean it anyway..

In theory im finding if i jump the red to brown on the switch harness plug i should get tail lights? Is that right?

 

[Hipster]

Check the ground thar connects to the frame in front of the bumper bracket on the left frame rail in front of the bumper brakt; clean, tight, corrosion free. Common issue.

 

[Ando069]

Check the ground thar connects to the frame in front of the bumper bracket on the left frame rail in front of the bumper brakt; clean, tight, corrosion free. Common issue.

Thanks... I just installed new headlight switch and ALL sorts of lights and buzzers started working... tails and dash fixed!... still no reverse lights... but just read a post here that says there is a nub in the shifter/mecbanism that may be worn... i'll get to that when my new hurst shifter comes in.. the one in there is seriously worn and i punch the dash when i go into 1,3...

 

[Ando069]

I'll add that my old switch had no positive stops what so ever... no "clicking" when you push or pull.. im not sure this is an indicator but if yours has no positive stops or clicking and you find your lights are doing strange things, whats to lose with a new switch for 20 bucks or so... you gain a new "clicky" switch and you may fix the light issue...

I do have a question on the on off switch under the headlight and dimmer... i have no clue what that should do... it has two orange wires going to it. Truck did have a trailer harness that i deleted.. was it for the trailer?

 

[Ando069]

Found it it turns on the light on top/rear of the truck... doh

 

[Andy Chevy truck]

If you haven't already, check if there's any trailer wiring plugged into your tail light harness in the back under the rear bumper. They're usually on a T connector and if they corrode or get damaged you can have issues like this. If there's anything plugged in back there I'd unplug it and hook the harness back together, then see if your reverse lights start working.

No power to my backup light switch. I have traced no power from backup light sockets to the switch. Where would I need to check next. I think I have a Blue and green wire at the switch. All other lights work.

 

[df2x4]

No power to my backup light switch. I have traced no power from backup light sockets to the switch. Where would I need to check next. I think I have a Blue and green wire at the switch. All other lights work.

If you haven't already, check this thread for the GM factory service manual for your year. There's probably some diagnostic info in there that will be helpful.

https://www.gmt400.com/threads/88-98-service-manuals.43575/