Cripes - Trailer Light issue

[EBass]

This is hard to explain and I think I know the answer, but maybe someone can help.

My lights on the trailer have been working for for the past 3 years. Then on Sunday night the driving lights won't turn on, but the signal/break lights light up nice and bright. My buddy had a tester with the lil light and deems that my truck doesn't have current for the driving lights coming off of the plug.

All my truck lights work and not one bulb is burned out on the trailer.

I take it home and troubleshoot and I find that there is current coming from the driving light (brown wire) Hmm, OK I replaced all the trailer lights and wires with a new set.

After the install which I sanded down the ground so it's nice and purrdy I'm back to the same issue I had before.

The break/signal lights are nice and bright, but nothing for the driving lights.

I then test the plug again and the brown wire barley has any power. I move the connector tester point and now I have good power. I plug it into the trailer and nothing for the driving lights.

AHHHHHHHHHHHH! I'm miffed and sure hope I don't have to start messing with the wiring on the truck, but it's looking that way. I think I have a bad ground somewhere, but it's not the trailer as the ground on there has worked for years and now it's all nice and clean, plus the break lights are bright.

Can anyone throw me a bone - I'm puzzeled.

I suppose have my buddy hook it up to his truck and see what happens. It'll prolly work then I'll be pizzed that my truck wires are F'd somewhere.

There's no fuse just for driving lights - is there? I haven't looked but doesn't seem likely as my driving light on my truck work fine.

Thanks for listening to be beeotch - and hope someone has an answer.

[18 inch Crappie]

Most newer trucks have fuses for the trailer lights, sounds like you have a bad plug or connector at the truck.

[Wade Joseph]

Id check the plug connection for the truck as well.

[fivebucks]

I was at my wits end with my truck the last couple of weeks. I had brakes and turns but no running lights coming from my plug. This was something that worked fine once and then the next time a month or so later it did not. I needed to take the truck into the shop for oil change and normal maint. and had them look into the trailer lights. It turns out the main factory harness went bad and they had to order another part. The truck is in the shop right now to have that part put in. I was going crazy trying to figure it out though.

[hanson]

Trailer Lights... gotta love 'em.

You may want to check the ground between your light housings and your trailer. Basically, the lights ground to the trailer through the bolts that connect them to the trailer. My lights were all goofy this spring and I found out the ground was bad there. The simple fix was to remove the lights from the trailer, clean the attachment holes out with a file, and reinstall the lights. They now have good ground and that fixed my problem. Not sure if it'll fix yours but its something easy to doublecheck.

[DinkADunk]

I had the same issues so I went to Burnsville trailer hitch and they replaced the plug on my truck in about 20 minutes. Problem solved

[EBass]

Thanks for the replies - It's not the ground as I sanded the heck outa it and sanded in the hole I drilled. Nice metal and the fact that the break lights are bright. If they were dim then I would check the ground again.

I think the plug coming off of my truck is bad, well the brown wire(driving light connection in the plug) The wiring all looks good though.

I'll give the Hitching post a call, otherwise I'll call that Burnsville spot.

Also, glad I'm not the only one with electric gremlins.

Thanks again everyone!!

[Jeremy airjer W]

So if you plud it in and check for power on the brown wire on the trailer side it lights up a test light but its real dim.

If you unplug the trailer and check the truck side of the connector for power on that circuit it lights up the test light bright?

If this is the case than that wire that feed power to the running lights is corroded somewhere on the truck side. The reason it is bright with the trailer plugged in is there is no load on the circuit or an open cicuit. It will read 12 volts on a volt meter or light up a test light all day long. Once a load is introduced and the cicuit is completed then the current has to first move through the the corrosion (which is a resistor at this point) which drops the remaining power thats available at the plug (dim test light).

Trace that wire back and I bet you'll find the problem.

[BobT]

One common problem I have seen is too often the ground (or dc return) is not taken seriously. It's amazing how often I find that some rely on the hitch to provide the connection rather than connecting the white wire on the 4-pin flat to the trailer frame or to the vehicle frame providing a good current path to the NEG terminal on the battery. This is usually evident when following a vehicle wired this way. Their lights flicker off and on as the hitch vibrates.

Bob

[EBass]

Quote:

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So if you plud it in and check for power on the brown wire on the trailer side it lights up a test light but its real dim.

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No driving light or any light on the tester when plugs together.

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If you unplug the trailer and check the truck side of the connector for power on that circuit it lights up the test light bright?

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It's weird it's dim at first then if I move the test pin around in the female plug I can get a bright light. I hook the connectors together, but leave a bit of the metal male connector exposed. The break lights are nice and bright, but nothing on the brown/driving wire. Same with the tester light.

Quote:

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If this is the case than that wire that feed power to the running lights is corroded somewhere on the truck side

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I can follow it to another connector then it goes to some other connector then into a cluster of something. I called the Hitching Post and they are going to take a look at it tonight.

You're right though - somewhere on the truck the brown wire is corroded(sp?)

[EBass]

Hat's off to the guys at Hitching Post. They took care of the issue in mins. I forgot what the name of the deal was that was bad. I had to buy some adaptor kit that is basically a complicated splice of the break/driving lights. Any who - thanks for the replies - case closed