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View Full Version : Trailer running lights and brakes wont work?


RedWingsDet
12-28-2006, 01:36 AM
I have a 2005 Enclosed 20ft Haulmark. The Lights on the inside, and outside lights wont work, however the tail lights work and so do the flashers and turn signals. Also, the brakes wont work and they are NOT registering on the contoller. and the breakaway isnt working.... One week its working, and the next week it wasnt.

Any idea what causes this? Do I need to re-wire the entire trailer?

Thank You.
Mark

KS_Grasscutter
12-28-2006, 01:53 AM
I have a 2005 Enclosed 20ft Haulmark. The Lights on the inside, and outside lights wont work, however the tail lights work and so do the flashers and turn signals. Also, the brakes wont work and they are NOT registering on the contoller. and the breakaway isnt working.... One week its working, and the next week it wasnt.

Any idea what causes this? Do I need to re-wire the entire trailer?

Thank You.
Mark

Check the trailer light fuse on your truck. If it is blown, you probably have a short somewhere. It is likely on the trailer. I know I had a similar problem on my trailer this summer, but finally fixed it. It was a wire that the insulation rubbed through and was touching the trailer frame.

RedWingsDet
12-28-2006, 01:55 AM
well sometimes the lights do come on, and sometimes not. so I wouldnt think it'd be a fuse. Im thinking it'll be hard to find where the wire would be touching the frame, since its an enclosed. It might be eaiser to run all new wires?

LindblomRJ
12-28-2006, 03:49 AM
I am thinking it might be a ground problem. Or a short of some sort.
Okay I will ask 20 quetions:

What type of tow vehicle?
What type of plug? What conditon is it in? Thinking about 6round or 7 pin and the inside of the plugs.

Have you checked, with a test light or meter the plug on the tow vehicle?
How is the condition of the gound on the tow vehicle, and on the trailer? Good metal to metal contact?
How about the connections at each of the lights and brakes.

It sounds like it is difficult to acertain the overall conditon of the trailer lights.

Most trailers from the factory seem to be wired fairly cheaply. If you do need to re-wire the trailer make certain that you use good quality wire with a good jacket.

Dstosh
12-28-2006, 09:45 AM
Check the trailer light fuse on your truck. If it is blown, you probably have a short somewhere. It is likely on the trailer. I know I had a similar problem on my trailer this summer, but finally fixed it. It was a wire that the insulation rubbed through and was touching the trailer frame.

I have had that happen also. It is most likely the culpret. Do you need to rewire? No probably not, but it will be a joy trying to find the short.

muddstopper
12-28-2006, 10:08 AM
Check the tow vehicles receptical first to make sure its the trailer and not the truck. If the Pins are dirty or corroded, get some battery terminal cleaner and spray on them to get them clean. Then check the ground wire, since your lights seem to be coming and going, the ground might be rusty at the connection and the trailer is having to ground thru the ball and hitch. You should be able to back up to the trailer and just plug in the wires and everything work, if it doesnt, then your ground wire is bad, either on the truck or the trailer. There is no other reason for the trailer wireing to be bad if it is enclosed, unless someone has been fooling with it. Check all connections with a test light and/or meter to make sure you are getting the rquired voltage. Less than 12 volts could also suggest a bad ground. If the wires have a break or are shorting out, you should be blowing fuses, you say you are not so I suspect a bad ground.

HydroCutter
12-28-2006, 10:34 AM
I had similar problem on a dump trailer. It was a ground problem. The bolt holding the dump level was loose, breaking the ground at every bump.

Dave

GreenN'Clean
12-28-2006, 10:56 AM
I had the same problem this past year and it was a loose wire under my dash board, i found a wire that wasn't taped properly and the wire was loose enough that every time i hit a bump it would short out. It was a cheap fix

LawnTamer
12-28-2006, 02:21 PM
On my enclosed, the tail-lights/brakelights run off the truck, but the brakes and the dome lights run off the battery on the trailer- if this is the case on your trailer, I would start by checking the battery terminals for corrosion and then start checking for shorts. If the brakes/lights cut out at the same time then the problem is pretty close to the battery.

LemkeLawns
12-29-2006, 11:29 PM
Are you relying on the Hitch and Ball to ground the trailer? If not wire a ground through the plug. Its worth a try.

stroker51
12-31-2006, 04:38 PM
From my experience, phantom sporadic light problems are usually due to a less than perfect ground somewhere, but I don't think I would go to the trouble of re-wiring the whole thing till you have elimated the ground possiblity or a bad connection at the plug.