Home Forums Gear Hunting Trucks and Four-Wheel Drives Trailer plug wires

Christ I hate trailer wiring. In theory it's SO simple, but in practice it's such a PITA. I need to rewire my stock trailer, but before I did so I made sure the plug at my truck was working right. Sure enough it's not. It's a 2012 Ram 2500, with factory brake controller. Running lights, turn signals, and brake lights are all good to go, but the trailer brake post just gives a steady trickle. And when you turn the gain down to 0 no difference, and when you turn it up to 10 no difference. Doesn't matter whether you have the brake engaged or not. I took it to the dealer and they said it needed a "flash update" for the computer and that might fix it. I left thinking it had worked since they didn't phoucing say it hadn't. I checked again today before I dove in on the trailer, and it's doing the same damned thing.

I've read that the factory brake controller is a weak point on these trucks. WTF?

Can't help you on the truck end. But this page has sure helped me on all the other wiring.

http://www.etrailer.com/faq-wiring.aspx

On my '08 Dodge, the light wires ahead of the jack are only 18ga. If you plug in a trailer with a few extra clearance lights, that's putting a real strain on the watts.
I'm rebuilding a camp trailer now and it's getting all LED lights just for that reason.

A couple years ago, I replaced the light jack on the truck, too. The stock one gave me all kinds of fits. Before you spend a wad at the dealers, check the brake wire ahead of the jack to see if you have good power there. It could be a problem in the jack.

If it's bleeding power when you don't have pressure on the brake pedal, it's got to be in the brake controller. You will have constant full power to the controller but there should be none after it until you push the brake. Also, check the emergency brake pedal if it has a switch to set trailer brakes. It might be sticking slightly on, enough to give you a drain.

Thank you gentlemen.

Are you sure you should be seeing full voltage on the trailer brake when no trailer is detected and when the truck is not moving? I think the factory brake controller uses the vehicle speed sensor and other doodads to regulate applied voltage.

I hate em too....rare that all mine work, very rare.....

BGG-
Can you swap a borrowed brake controller to see if that's the problem?

I think I'd start there before redoing the trailer.

Good point. I do seem to remember reading something about that now that you bring it up.

Try the trailer on the road before doing anything expensive.

Can't help with the break controller, but if you're going to rewire the trailer, go with tinned 14 ga marine wire, sealed led lights, heat seal wire splices and run ground wires to the lights vs. using the trailer for the ground.

Yes, it'll cost more up front, but you'll save yourself all the grief of having to trouble shoot the trailer wiring every time you hook it up.

That sounds like a man talking from long experience!


Add me as another who hates trailer wiring! Would have thought things would be controlled by a wireless connection by now..

Agree with K1500. When testing voltage at the truck connector on my 98 Dodge, unless the brakes are engaged fully, I only get small voltage/amperage at the connector. If that brake magnet is engaged to the trailer wheel brake surface, you will not get it to pull any amperage.

[bleep] trailer lights/plugs all [bleep] suck [bleep] donkey balls.

Took the words out of my mouth.

I think I got the quote from Dan in Alaska's dad, but I'm not sure where he got it:

"In the beginning, man created the wheel. The trailer soon followed. And we've been trying to get the [bleep] trailer lights to work ever since."

There's an excellent treatise on this subject that's worth reading. It's titled 'Trailer Trials' by Pat McManus.

Gotta remember that one!!

Thanks for all the help guys. I'd never heard that stuff about the damned truck needing to be hooked to a trailer for the plug wires to work. What goat rope.

Trailer wiring just never works for me. I've rewired with cheap trailer wiring, old extension cords, heavy wires, I solder, heat shrink, and tape all the connections, ground each light, etc. Will work for a while, then inexplicable go kaput. But I have not ever put in the LED's before. I'll give them a go this time.

LED's alone won't cure your problems, good wire is a must

[img]http://i.ebayimg.com/00/s/MTYwMFgxNTEx/z/baUAAOSwDN1US~b7/$_35.JPG?set_id=880000500F[/img]

and sealed splices



and use some dialectric grease on the plug connection

I hate trailer wiring with a passion. Last fall I helped my dad troubleshoot the lights on his duck boat. He replaced nearly everything end to end and things still weren't working right. We diagnosed for 2 days with a meter and test light and basically rewired the thing tongue to tail only to have it not work. We reassembled everything just as he had originally installed it only to have it start working, we still don't know what we changed that fixed it. For what should be such a simple system they can be a real pain in the ass.

First thing you should do is determine if the trailer uses a ground through the connector or the trailer tongue. This can cause quite a bit of confusion and throw you off on your troubleshooting.

This link really covers just about every application out there.

http://www.etrailer.com/faq-wiring.aspx

I highly recommend using sealed splices instead of the cheap crimp type, if you have to use the crimp type put a piece of heat shrink over it to seal the splice.

Wrap the spliced area with some electrical tape and finish using a section of wire loom tied off with wire ties. That's how I always fix my trailer wires and it makes it look professional too.

use a soldering iron those crimp connectors suck in an area with vibration and movement. also the most important thing to start with is make sure the dang thing is grounded. espeically with those 4 flat style connectors. the white wire is ground nothing will work unless that is grounded.