Anyone with a tail light issue?

Pauleo · Post by **Pauleo** » Sat Oct 16, 2004 11:54 am

All of a sudden, my tail lights are screwed up! But only when I turn on the headlights! They are fine with the DRL's on. And no, I have not done any headlight mods. All the bulbs are fine, cause tey all work when the headlights are off. But turn them on and the right turn signal blinks real fast, BOTH back up lights come on and flash too! I have a funny feeling it has something to do with the trailer harness but I don't know. I had U-Haul put my hitch on, the wires were already there. But maybe they fooled with something under there? Of course they deny having any responsibility for it even though it started right after that install. Am I close on this one or does anyone have any other suggestions?

Post by **HenryJ** » Sat Oct 16, 2004 12:11 pm

Sounds like U-haul messed things up for you

If they told you they did nothing and the wires were already there, that is somewhat true...the wire were there for the taillights, but not for the trailer

I really sounds like something is shorted out , so get this fixed quick.

See the two plugs in this picture-

Those are what is needed to have the factory trailer light wiring kit. Yours may only have one connection for the harness'.

I would suggest that if you do not have the factory "plug-n-play" connection, go to your local auto parts walmart , or farm supply , and pick up a plug in trailer wiring set. There are a few companies that make simple plug in tee connections. Hoppy is a popular brand. The Part # 41135 is the right one and this is what it should look like-

Take out all the line taps and splices that I would imagine they have "hacked" into your wiring and throw them right back at them, or just into a trash can. Be sure to carefully tape up all the wires that were exposed.

Now I hope that I am wrong, but look under there and see what kind of a mess they have made. If it is as bad as I am imagining and there are some of those splice taps (see the one in that picture above to the right of center), do what I have suggested above. If it does look like a "plug-n-play" connector, and no splices then post back here, and we'll try plan "B"

While we are at it this is the connector that I use-

It has both the round 6 connector for my trailer, and the flat four for the boat. It too is "plug-n-play"

Pauleo · Post by **Pauleo** » Sat Oct 16, 2004 12:29 pm

Man! That was a fast reply! THANKS!!!

Actually, I must have miss typed. The harness and all WAS already there. it was just tied up or something to where I couldn't get it out to hook up to the trailer. But it was already there. They just "pulled" it out and supposedly cleaned it so I would have easier access.

Post by **HenryJ** » Sat Oct 16, 2004 12:39 pm

Do me a favor and go out, crawl under, take a look . See if it looks just like the picture above, less the splice tap that I added for the back-up light.

That is a GM factory trailer wiring harness connection.

Make sure that they did not leave a splice pack unplugged , or a ground terminal disconnected while you're under there. Check for pinched wiring caught under the mounted hitch too.
I have seen some really bad U-haul "expert" wiring jobs

You are having these problems all the time, not just when connected to the trailer, right?

quickbiker · Post by **quickbiker** » Sat Oct 16, 2004 1:48 pm

Make sure the ground wire is going to a good ground. That will always wack out the rear lights.

Pauleo · Post by **Pauleo** » Tue Oct 19, 2004 5:32 am

You are THE MAN!!!!

It was the grounds at both sides! I wouldn't put it past those guys to have loosened them so that they could charge me an extra 60-70 bucks to have them install one of THEIR trailer wire harnesses! Know what i mean?

Anyway.... I really appreciate your help. THIS BOARD IS AWESOME!!!!!!

..........New problem though........ now the truck won't start! Unrelated. I think it's the fuel pump. It was so sad to see my little red baby being pulled up on that flatbed tow truck!

kf6kmx · Post by **kf6kmx** » Tue Oct 19, 2004 11:07 am

quickbiker wrote:Make sure the ground wire is going to a good ground. That will always wack out the rear lights.

That was going to be my suggestion..
If the lights are 'normal' with the headlight swtiched off, the system is grounding back through the circuit.. when the lights are on the ground path is hot and the lights go goofy trying to find routes to ground.. Have seen this a hundred times (have a lot of friends with RV's / race trailers) Its a common problem when a u-haul dealer works on your lights (about 40% of the ones I've seen get a uhaul light install come out screwed up somehow.. once with ALL the wires on the wrong pins in the plug..

)
It happens sometimes just from a bad connection or rock damage.. I had that happen on my 1-ton.. I was pulling a trailer and a rock kicked up and hit right on the harness where by ground wire was and cut it off .. had to do a repair while I was at the campground,,

Pauleo · Post by **Pauleo** » Wed Oct 20, 2004 7:22 am

Well, I got a call from the dealership today about my truck not starting. The ground wire for the fuel pump was ripped out when I the wonderful guys of U-Haul installed my trailer hitch! Apparently it was just hanging on by a thread so when I tightened the bolts for the grounds on the tail lights (that they also loosened), it broke it completely loose!!! The good news is that I'm not getting charged for the service or the tow bill!!!! Got an extended warranty and they're handling it!!!

The bad news was having to go through that dreaded experience of seeing my pretty red CC rolling down the street on the back of that flatbed!

Oh well. I guess I should just be happy that it was nothing major.

kf6kmx · Post by **kf6kmx** » Wed Oct 20, 2004 7:49 am

Pauleo wrote:The bad news was having to go through that dreaded experience of seeing my pretty red CC rolling down the street on the back of that flatbed!

Oh well. I guess I should just be happy that it was nothing major.

At least its fixed

When I had my 1-ton dually, the alternator siezed up once when I was in town.. It came home on a flatbed towtruck.. Talk about a site I wish I had a camera for.. my truck was darn near bigger than the truck it was riding on! the rails of the tow truck were between my duals in back on both sides, and you wouldnt believe how top heavy that top truck looked!