Trailer brake problem...

[Baucom]

2007 Nissan Titan tow vehicle with a 6 pin trailer plug and 7 pin on the truck. Using a Hoppy 6-7 pin adapter. Nothing has changed in my towing setup in the past 2 years and it has always worked until the LH brake hung this time. The heat index here has been too HOT to pull the trailer in the driveway and work on it...hopefully in a couple of days it'll be back down in the low 90's and I can test a few theories.

It would seem to me that since the setup I have has always worked in the past, and since the RH brake is functioning properly, that whatever is wrong must be either something mechanical inside the brake drum or in the wiring that runs into the LH brake assembly.

My gut says the problem is electrical, because the LH brake only hangs when the lights are plugged in. I can pull the trailer all day without the wiring plugged into the truck with no problems, but when I plug in the trailer wiring to the truck, I pull up 2 feet and the left wheel is sliding. If the problem were mechanical, such as the magnet stuck to the drum or a foreign object jamming the brake band, then it should happen all the time, not just when the lights are hooked up, right?

 

[Soundguy]

only fly in the ointment is those brakes are paralleled. have to be. there is only 1 sypply line on the plug for both magnets.. that means the 1 wire int he trailer plug runs to both magnets.. thus if power was shorted over to a wire near the left axle.. the right axle would see it too.

if it was electrical.. it would make me think the brake not locking up was simply not working..

soundguy

 

[Soundguy]

ps.. didn't repalce that 6 to 7 pin adapter did ya?

soundguy

 

[Baucom]

No, it's the same adapter I've been using for the past couple of years.

ps.. didn't repalce that 6 to 7 pin adapter did ya?

soundguy

 

[Skyco]

Good point on the 6 to 7 pin adapter..I found out years ago there are two "standards" for 6 pin wiring and the wrong one will cause brake problems.
Went down the street with someone elses trailer and had brake problems.
It had the other "standard" for 6 pin wiring.
Some 6 pin adapters point this out and have a quick change provision to swap two wires.
http://www.hopkinstowingsolutions.com/doc/trailer_wiring_codes.pdf

 

[Diamondpilot]

Like SG said the way they are wired is one wire runs from the tongue down one side of the trailer to the first brake. It then runs across the axle to the second brake. I think this is where you will find the issue from what you have told us. My guess is a wire is chaffed. Sometimes they run though the axle so be careful pulling a new wire through.

Chris

 

[forester2]

Don't know if this will help, but I had a problem with both brakes locking up that drove me crazy. Finally traced it to the plug on the trailer side. One stray strand from the brake wire was touching on an adjacent light terminal. My plug was the style where the outer covering was removable to run wires into screw terminals.

 

[Soundguy]

yep.. my hopkins adapter was a quick change.. just remove a screw slide apart, swap 2 wires and go..

soundguy

Good point on the 6 to 7 pin adapter..I found out years ago there are two "standards" for 6 pin wiring and the wrong one will cause brake problems.
Went down the street with someone elses trailer and had brake problems.
It had the other "standard" for 6 pin wiring.
Some 6 pin adapters point this out and have a quick change provision to swap two wires.
http://www.hopkinstowingsolutions.com/doc/trailer_wiring_codes.pdf

 

[Soundguy]

my dexter axles on my 16' were that way.. no grommets.. just single insulated wires run thru.. and chaffed. I ran dual insulated wires, and pushed some 1/4" fuel line onto the holes as grommets. been fine since. also had some chincey tap fold over splices from the dealer.. replaced those too with sealed connectors

soundguy

Like SG said the way they are wired is one wire runs from the tongue down one side of the trailer to the first brake. It then runs across the axle to the second brake. I think this is where you will find the issue from what you have told us. My guess is a wire is chaffed. Sometimes they run though the axle so be careful pulling a new wire through.

Chris

 

[Iplayfarmer]

I have one fix for trailer wiring problems... I rewire the whole thing. I've never spent less time chasing a gremlin than I would have spent just running new wire. I buy any extension cord I can find at garage sales, auctions, etc. so the cost of the wire is negligable.