Trailer brake lights not working (but everything else is)

Sorry for another trailer wiring question, but I just didn't see the answer I was looking for.

Here's the facts.

I just have a little 4x8 utility tilt-trailer. Running lights work, blinkers work, brakes do not. I checked all fuses and they all lit up with my test light. I installed a brand new wiring kit (new lights and wires) due to multiple splices and it just looked like the old one was in bad shape. I have probed the connector behind the driver tail-light and have 3 hot (for the colored wires) and 1 ground (for the white). Probed along the extension that gets the wires out through the tailgate. All have juice. Probed wires just after 4-pin connection-all have juice. Started probing along driver side the yellow (brake) and brown (running) wires. I get to a point where I cannot probe anymore because my test light cannot find a good ground on the trailer frame.

I'm thinking that between the layers of paint and the rust, the trailer frame has a sketchy ground. I'm picking up a grinding bit for my electric drill and I'm going down to bare metal wherever the lights and my ground connections touch the trailer.

Do you think this will solve my problem?

 

[Joe Dirt]

It could. Another thing to check is if you have a flexible license plate mount and have the light attached to it and not the frame, you may need to ground the light to the frame separately. I had to do this with my trailer to get the lights to work correctly after installing 2 sets of trailer wiring and tearing all of my hair out. I HATE trailer lights, they're the biggest PITA ever.

Yes, ever.

 

[99XLTBiker]

After spending several hours out in the driveway getting a sunburn trying to figure out the light problem, I agree with you completely Joe.

I'm bolting the lights directly to an angle that's welded to the frame. I even took the extra step (as the instructions suggested) to run a ground wire from one of the bolts to the frame itself. But again, if I'm having trouble getting a ground for my test light to work, methinks that I'm not properly grounding the lights either via the bolt to the frame.

I'll report back after I'm sure I'm attaching the grounds to clean, bare metal.

 

[99XLTBiker]

Okay, I took a grinding wheel to the frame tonight and everywhere I touch the frame (lights bolt to the angle in rear, ground wire going from one of the bolts to under the frame, ground wire at the front from the 4 pin connector. And still nothing. Everything works but the breaks. I still can't get my test light to work near the rear even though I grounded off a couple of spots under the frame to connect to.

Do you guys think it has anything to do with me having a tilt-bed? I mean, could the rear of the trailer not be grounded properly with the front because it can separate when it tilts?

All things being equal, if the X is properly grounded, and I connect up to it, I should then have a good ground via the white wire. But if that connection is broken where the trailer tilts, could that cause an issue?

I'm about out of things to check!

 

[Joe Dirt]

Did you try grounding the lights themselves directly to the frame? This is what I had to do:

I had to wire the posts on the lights directly to the frame. One of my turn signals were merely turning the running lights off, and my brakes didn't work like yours, now they work great...

 

[99XLTBiker]

Did you try grounding the lights themselves directly to the frame? This is what I had to do:

I had to wire the posts on the lights directly to the frame. One of my turn signals were merely turning the running lights off, and my brakes didn't work like yours, now they work great...

Yes, I did that Joe (I think, I'm at work and I can't see the pic you provided until I get home). I ran a separate ground wire, wrapped around one of the bolts on each light, and attaching via a screw to the underside of the frame.

I'm thinking of doing something extreme but it may resolve my issue. I don't think I can trust the trailer frame at all for grounding. What if instead of grounding my white near the tongue (where the white wire comes from the 4pin connector) and then grounding my lights to the frame I did this. Run a solid ground wire from each light all the way up front and attached directly to the white wire coming from the connector. I would totally remove the frame from the grounding equation. Assuming my X has a good ground, this should solve my issue, no?

 

[99XLTBiker]

VICTORY!!!

I picked up some 16 guage wire on the way home. Connected to one of the bolts that secure the light to the frame and connected the other end directly to the white ground coming from the 4 pin connector. Did this to both sides (just ran it along under the frame along side the two hots going down each side). Turned my lights on and VOILA! Everything works, including brake lights for the first time!

The frame had to have been my problem. Between the two layers of paint and rust, there wasn't a good ground to be had. So I bypassed the frame entirely and I'm grounded via the white wires only that are grounded by the X. Success is mine! Now, time to go to the home stores to pick up building materials to finish my basement! And after the basement's done, it's going to become my motorcycle hauler!

 

[Joe Dirt]

Thank freakin God. What a pain- there should be a firing squad- the guy who set up trailer lights should be plugged right after the moron that invented flathead screws.

 

[99XLTBiker]

Thank freakin God. What a pain- there should be a firing squad- the guy who set up trailer lights should be plugged right after the moron that invented flathead screws.

Amen Joe! Thanks for your help. I was about to give up and run without the brake lights chancing a ticket or worse.

 

[Joe Dirt]

Glad she's on the road to fun.

 

[Sporttrac715]

License plate

It could. Another thing to check is if you have a flexible license plate mount and have the light attached to it and not the frame.

This was most helpfull. Everyone with this problem please try removing license plate holder and attach light directly to trailer. It will save you much agrivation. thanks Joe!