S-10 Tail Light Problem

Huntn · #1 08-22-2007, 08:00 PM

A relative borrowed my 1998 S-10 to do a U-Haul tow. It's the off-road version. Sometime after I got it back I noticed that both the left tail light and the white light that illuminates the rear tag are no longer working. I took the tail lights out and notice that both of the light bulbs for the tail lights have harnesses added for a trailer hookup. Everything on the right works but the left side is not illuminating as described above. For the trailer hookup, it really does not look like any of the original wiring was tampered with so trailer may have nothing to do with this problem.

I've done some trouble shooting, exchanging bulbs and I have verified it is not a bulb problem. I've also checked several fuses and can't find any that are blown. So whatever it is, is effecting both the left rear tail light and white tag light. Brakes lights work ok.

Any leads would be appreciated. Thanks!
-Dave

blazes9395 · #2 08-22-2007, 11:06 PM

Assuming your fuses are good, you'll most likely have to back probe and find the open in the wiring. If the trailer wiring was pulled a little too much, it could have caused the connections to become loose and give you an issue such as this.

Good Luck!

oh and welcome to AF!

Smokefan20 · #3 08-23-2007, 01:16 AM

Not sure if i should jump on this post or start my own...But i am haveing almost the same problem. But i have not done any towing or anything like that. And the bed has never been removed. Its a 98 s10 2.2 manuel. My right side tail lamp and right side tag lamp are out. Replaced bulbs and checked EVERY fuse! Even swapped the bulb from the left to the right taillight. The brake light works...The turn signal works. But no taillight. If anyone has any thoughts you would be helping out atleast two of us! THANKS!

Huntn · #4 08-23-2007, 06:47 AM

Smokefan,
Very interesting! What could it be? There are covered cable bundles back there and I was really hoping to find an answer before I start taking those apart.

Huntn · #5 08-23-2007, 06:51 AM

Quote:

Originally Posted by blazes9395

Assuming your fuses are good, you'll most likely have to back probe and find the open in the wiring. If the trailer wiring was pulled a little too much, it could have caused the connections to become loose and give you an issue such as this.

Good Luck!

oh and welcome to AF!

I looked at the fuse list for something that might be related. I checked things like the RRLGT and LRLGT, BKLGT, etc but all of those fuses were ok. Maybe it's something with a weird name? For the S-10 does anyone know what fuse controls these lights?

Thanks for the welcome!

Smokefan20 · #6 08-23-2007, 08:03 AM

Just got done messin with it AGAIN. I just took the grounds off, Ground them down to the bare metal and put em back on. Still no luck. But it did bring up another question. There is a ground on both sides. On the right side there is one ground (the side not working) On the left side there are two wires grounded (the side that IS working) I know that one of them on the left is the fuel pump ground. Is the other the left tail ground? Is left and right grounded seperatly?

Smokefan20 · #7 08-25-2007, 05:10 PM

I THINK i might have the problem narrowed down to one of the trailer harnesses. There are three. Two small ones on the sides and a big one in the middle. All with the metal teeth on the caps. If i take the cap off of the middle one, both taillights act the same. With everything working except the tail lamp and side marker.

Seriously...I have a headache! Any suggestions? What would happen if i would cut the harness off?

Smokefan20 · #8 08-25-2007, 05:29 PM

Just got done using the bulb tester on the center harness. I only get a light on wire E. Is this normal? Sorry to keep posting, But i dont know where else to turn with this. Thanks!

muff34 · #9 08-25-2007, 06:15 PM

the only thing you can do if you know the bulbs and fuses are good is to start probing with a test light,just like blazes9395 stated. . follow the wiring to the front ,looking for joints if you find any give them a tug and look for corrosion. when you pick /probe a wire seal it with finger nail polish to keep moisture out . three trailer harnesses on an s-10????

Huntn · #10 08-26-2007, 09:37 AM

Quote:

Originally Posted by Smokefan20

I THINK i might have the problem narrowed down to one of the trailer harnesses. There are three. Two small ones on the sides and a big one in the middle. All with the metal teeth on the caps. If i take the cap off of the middle one, both taillights act the same. With everything working except the tail lamp and side marker.

Seriously...I have a headache! Any suggestions? What would happen if i would cut the harness off?

I looked at the center and side harnesses you mentioned. I don't get the metal teeth, they look like connectors. Are they supposed to function like fuses? All of mine look normal. The search continues!!

Huntn · #11 08-26-2007, 10:54 AM

Quote:

Originally Posted by muff34

the only thing you can do if you know the bulbs and fuses are good is to start probing with a test light,just like blazes9395 stated. . follow the wiring to the front ,looking for joints if you find any give them a tug and look for corrosion. when you pick /probe a wire seal it with finger nail polish to keep moisture out . three trailer harnesses on an s-10????

My S-10 has 3 connectors right behind the spare tire. One large one in the middle and one on the left and right. I don't know what they are for. When pried apart, there are 3 pronged connectors that look like little forks. What are these for? And could they be related to the stated problem?

All of the wires are in a plastic bundle. Eventually if I can't find the source of the problem I'll start pulling wires out and physically following them. I really hope the problem is isolated to the rear part of the truck.

Smokefan20 · #12 08-28-2007, 01:45 AM

What happend to this thread? Was it taken down? If so...WHY??
I guess i wont get any answers here!

Huntn · #13 08-28-2007, 10:47 AM

Quote:

Originally Posted by Smokefan20

What happend to this thread? Was it taken down? If so...WHY??
I guess i wont get any answers here!

What do you mean? This thread is still up.

Huntn · #14 09-01-2007, 06:54 AM

bump

Huntn · #15 08-10-2008, 07:56 AM

Somehow I forgot to post a resolution to this problem.

In regards to my left taillight and left tag light, I had a blown fuse. What I discovered was that my fuse diagram in the owners manual was not correct. When I took a close look at it, there was a spare, unmarked fuse, next to the fuse designated in the diagram as the one supposed to control those lights. So I checked it, it was blown and I corrected the problem by replacing it. I had considered ripping up wiring in the back of the truck, even running a wire from the good side to the bad side. Thank goodness I made more checks on the fuses first.

-Dave

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