Trailer tail lights no workie, but turn signals & brake lights do

[6716]

Going to be pulling a 6x12 Uhaul trailer this weekend. The guy at the place checked the electrical at the trailer plug, everything works but tail lights.

Looked at the fuses, the "TR Park" 10A was good, that's the one they guy thought was the correct one.

I'll go looking at the ground here in a minute, but I wanted to get a thread started ASAP.

If it isn't that, what else should I look for? I almost never tow, and electrical makes my brain hurt.

Thanks.

 

[Grimor]

Going to be pulling a 6x12 Uhaul trailer this weekend. The guy at the place checked the electrical at the trailer plug, everything works but tail lights.

Looked at the fuses, the "TR Park" 10A was good, that's the one they guy thought was the correct one.

I'll go looking at the ground here in a minute, but I wanted to get a thread started ASAP.

If it isn't that, what else should I look for? I almost never tow, and electrical makes my brain hurt.

Thanks.

hook the trailer to something else and make sure it works before stressing too much

 

[6716]

hook the trailer to something else and make sure it works before stressing too much

never hooked the trailer up, the guy had some tool or another that showed the problem. The 7-wire to 4-wire adapter I have also has some lights that are supposed to show something, but I don't have the original documents.

But I suppose the tool might have been off ....

THE REAL PROBLEM NOW IS THAT when I wrenched on the bolt head for the ground wire, it broke off ... now the ground wire is loose, but the bolt is still through the spot, and I haven't figured out how to get the bolt out so I can re-attach the ground after I clean it up.

shoot ...

 

[Grimor]

never hooked the trailer up, the guy had some tool or another that showed the problem. The 7-wire to 4-wire adapter I have also has some lights that are supposed to show something, but I don't have the original documents.

But I suppose the tool might have been off ....

THE REAL PROBLEM NOW IS THAT when I wrenched on the bolt head for the ground wire, it broke off ... now the ground wire is loose, but the bolt is still through the spot, and I haven't figured out how to get the bolt out so I can re-attach the ground after I clean it up.

shoot ...

drill it or a spot next to it and use either a self tapper (I guess you don't really need a drill then) or a nut and bolt.

 

[The_Roadie]

...electrical makes my brain hurt....

Willing to buy a voltmeter and learn?

Spoiler

Or open your wallet for folks who have that gene. Like me.

 

[6716]

Willing to buy a voltmeter and learn?

Spoiler

Or open your wallet for folks who have that gene. Like me.

Well, I suppose I'm a trainable monkey.

Off to the store here in a minute to get a bolt for the new hole I drilled for the ground connection.

Any special type I ought to get?

 

[6716]

Well, of course, it wasn't the ground. But it shouldn't be in the near future, either, after I cleaned it up.

Went back to Uhaul, the guy was saying it was the brown wire, and he's been doing it a lot of years, and I suppose he'd know. Put the light thingy on the brown wire, and there is power right up until it starts hitting the connectors, and then it doesn't come out the end where the trailer plugs in.

So how do I get those two bits out to inspect and clean up? I have a habit of breaking the tabs on connectors, rather not keep doing that.

New part at the local dealer is $80 for the final connector, and I didn't price out the one just upstream.

Oh, and I got the $20 voltmeter at AAP. Now what?

 

[6716]

OK, have the connectors apart, still want to get the trailer plug connector out of the frame.

How am I going to do that? It's supposed to rotate or something or something or something .... right?

 

[6716]

See, you f#$&ers know me by now.

"Ah, don't bother replying, he'll figure it out. He's just whining. You watch, two more replies and he has it fixed."

So I got the last connector out of the frame. There's some corrosion around the ground wire connector, but it looks like the real problem was that the #6 pin was bent out towards the edge of the connector and probably wasn't even making contact with the harness end.

Cup of coffee says that's the deal.

Now I just have to clean up a little corrosion ... but not much.

 

[Porkins]

See, you f#$&ers know me by now.

"Ah, don't bother replying, he'll figure it out. He's just whining. You watch, two more replies and he has it fixed."

So I got the last connector out of the frame. There's some corrosion around the ground wire connector, but it looks like the real problem was that the #6 pin was bent out towards the edge of the connector and probably wasn't even making contact with the harness end.

Cup of coffee says that's the deal.

Now I just have to clean up a little corrosion ... but not much.

Alright, now you only have one more post intill you get it fixed.

I use a probe tester like this one to troubleshoot my trailer problems.

 

[The_Roadie]

...get a bolt for the new hole ...
Any special type I ought to get?

Threaded. You don't have a junk box filled with old screws? Man, you gotta go to some dead old fart's estate sale and pick that stuff up. Somebody's going to have a field day after I kick off and Mrs. Roadie sells my junk.

... I got the $20 voltmeter at AAP. Now what?

Practice using it. On the battery first. Put it on the auto-voltage range if you have one, otherwise, the voltage range just a bit higher than the 12V signal you're measueing. Like a 20V range is you have that. The meter should have come with a pamphlet.

 

[6716]

All good on all that.

Other than the ground looks like a third grader drilled it out and re-did it, everything is back together.

Got some electrical connected cleaner at AAP to help with the corrosion, then put it back together with dielectric grease.

Trailer lit up just like it's supposed to.

So thanks, y'all.

Only problem now is a transfer case leak ... but I'll start a new thread on that.

 

[ElAviator72]

The tail light fuse is in the fusebox under the back seat on the driver's side...I've changed that one a few times due to faulty wiring in my trailer (usually, the brown wire chafes through somewhere on the trailer frame and shorts out) Pull out the owner's manual, find the fuse, and change it (not a bad first step). Once you've done that, get the $5 plug at the auto parts store that plugs into the 4 pin adapter and has LED's to show you what is working...in my experience, bent and ill-fitting pins in 7 to 4 harness adapters aren't uncommon at all