Unusual wiring situation

[Dirtleg]

To start I just installed my new Tekonsha P3 thursday. I have been waiting and waiting for the Jordan to be re-released but it has not happened. My controller tells me that I have no trailer connection with the trailer connected. All my lights work fine BTW. No brakes however.

So I start checking the wiring on the trailer. I have known there would need to be some cleanup as the breakaway switch has been bypassed and there was only 1 wire going to the battery for it. I started fooling with the connector (6 pin) and noticed everything had continuity to ground except for the center pin (aux). I then noticed that the wire going to the center pin was broken about 3 inches into the loom. So I checked for continuity on this wire and it gave me a reading at every pin.

At this point I decided to go ahead and start removing the breakaway switch battery box. The red wire coming from it was the broken center wire ? The were no other wires going into or out of the battery box. How in the hell I was getting continuity on this wire I cannot guess. I have physically looked at all the wiring under the truck and although it is quite a hack job I cannot find any places where it's worn through. It's all run through insulators at the body points. And like I said the lights all work (including brakes and turns). Even with continuity at every pole. The only wires I couldn't visually inspect were the ones in the axle tubes for the brakes.

Is there something fundamantal I am missing here?

Now I am thinking that the way the controller works is it detects ground on the brake wire. That's how it knows if you have a trailer connected or not. Then to apply the brakes it just adds voltage as needed. So I can understand why there would be continuity to ground on this wire. But why the rest of them have continuity to ground has me baffled. Unless it's just continuity through the bulbs. I suppose that could be it.

Thoughts?

 

[Dirtleg]

Well, it's finished finally. I went ahead and fixed all of the wiring issues with the truck and trailer.

To start I went ahead and rewired the breakaway system back into the brakes on the trailer. I first verified that the switch was operating properly. Then I connected the battery and charger to one of the truck batteries to see if the charger was working. It was but the battery wouldn't hold a charge so I'll need to get a new battery for it. I checked all the wiring connections at each lamp and brake. I did find a few jacked up spots in the wiring and eliminated any potential shorts. Then I replaced the 6 pin connector with the one from my 6 to 4 adapter because it has a short inside it. Strange for sure. Unfortunately I still didn't have a trailer connection at this point.

So it's on to the truck. My truck has the factory 7 pin connector that plugs into the harness. It is an unusual round pin 7 pin plug. The person that had installed my gooseneck plug did a hack job and cut the wires on the adapter harness and spliced into it. However they only spliced in the lights. They left the brake wire disconnected. I didn't want to cut into any more wires in the factory adapter so I ran a wire from the in bed plug to the 7 pin plug that feeds the plug on the bumper. The brake connection wasn't working on that plug either so I didn't feel at all bad about putting the wire in it. I'll just have to remember to correct all of this mess once I am home again. It'll work well for now but is not ideal by any means.

So anyway now everything is working properly except for the breakaway battery. I made some detailed notes on the factory wiring plugs where they connect to the factory adapter and will draw a schematic when I get the time. Glad that's done.

 

[Dirtleg]

Continuation of saga. Yes everything was working but I just had to go and fix it again. It was a band-aid job and I was honestly ashamed of the condition it was in.

So today I went ahead and removed all of the splices into the factory harness. I just butt-crimped the already cut wires back together for now and will probably solder and shrink wrap them once I'm at home. During this process I realized the running lights were all being fed off of the license plate light wire. It was wired to back feed into the the factory trailer wiring. Why anyone would rather do that than replace a damn fuse is beyond me. Yes the #4 fuse in the power distribution box was blown. Probably got ahold of a bad trailer in it's previous life.

I removed the 6 pin connector from the bed prior to checking the fuse and spent forever trying to get the bolts off and on. Whomever installed it put it just forward of the rear tank filler neck. So I had to contort my left arm with a wrench up into no mans land and then reach over the bed rail with a ratchet in my right hand to loosen the bolts. They were unusually long with nylocks on them. Not anymore.

I connected the in-bed receptacle directly to the 7 pin RV plug that connects to the factory receptacle. No more jimmy-janked wiring under there now. I did lose the bumper receptacle wiring in this process but don't plan on using it right away anyhow. When I do replace it it willl be with a new, modern 7 pin as that is what our horse trailer has. It's bumper pull too so perfect.

I also replaced the 4 broken marker lights on the trailer. A PO had screwed some different ones to the frame of the trailer and rewired them rather than replace the rubber mounted push in-out original lights. Must be a Texas thing. I just got the original style and a couple of new plugs to replace the 2 missing plugs and put it back the way it was meant to be originally.

And much to my surprise NAPA had a battery for my breakaway switch system. It wasn't listed in any kind of easy to find way but I got the salesperson to go through a book with me and I saw what looked like the right one. I got lucky as it was identical to the old one and fit perfectly.

Now since all my wiring is up to spec and there is nothing else that could cause my trailer brakes to not work well it is time to start troubleshooting that issue. Never ends. They work but so little as to be useless. You can feel them drag a little if you are cruising and flip the engagement lever all the way over. I've got the controller turned up to 12 volts just to get that. I guess I'll adjust them first and then see what it's like. Man I hope I don't have to do 4 drum brakes right now.

So there you have it. Getting there but slowly. I need to quit buying used junk. Getting them up to ***** is eating up all my time lately. I have never been one to want new equipment but it's looking better all the time.

 

[Dieselmaster]

Dirt Leg,

It's been an interesting read! Good luck!

I wansn't sure if you had ever seen these style of connectors before. They are crimp, heat shrink and solder all in one. I use these on our race truck... They work great... but you need a really good heat gun to activate the solder...

http://www.delcity.net/delcity/servlet/catalog?parentid=791843&page=1

 

[Dirtleg]

Thanks for the link Dieselmaster. I have seen something like those before but it was for big industrial wires. Those are nice I just don't know if my heat gun will go there.

I am seriously considering putting an electrical enclosure under the truck and making a "Base of operations" for any and all trailer wiring related issues. I would use terminal blocks, circuit breakers and relays with all power pulled on a big fat wire directly from the battery. Protected of course. The factory wiring would be used to energize the realys only. All the wires in/out would run through sealed connectors into the enclosure.

You could mount switches in the cab to control backup lights or accessory trailer power and even use it to run a backup camera from the trailer to the truck if you wanted. All sockets would be pigtailed out from there to reduce the size of any openings that would need to be sealed up.

Hell you could mount a PLC in there and use it to control a robotic arm to fire paint balls at tailgaters. Just mount a joystick up front and some servo motors on the arm. Good to go. But I think that might be illegal

 

[Dirtleg]

Alright one last entry in this saga. Trailer brakes just needed adjusting. Now they will hold the truck and trailer on a significant grade by themselves. Turned the brake controller down to 8.4 and they held fine. I'm thinking a little use to get them fresh again and they'll work well. While I was under there I noticed the brace that goes in between the center spring pivot mounts had broken off on one side. An inspection showed that the weld on one end had zero penetration and that's why it broke. So I went ahead a rewlded both sides of it to fix it and make sure it wouldn't come off on the road. An 8 ft piece of angle iron could kill someone if loose on the highway.

I welded on the 2 new D-rings I bought since I had the welder over there anyway. Then I inspected the wheel bearings and one of the sets of brakes by removing the hub and drum. All good there so trailer is ready to go. Finally.

Truck is ready too. I am ready as well but have to finish up something here first. Should be on the road by Friday. I was hoping to do the drive during the week but it can't be helped. Lets pray the 1500 miles goes smoothly.