Elect trailer brake problem

[George2615]

If the trailer was wired to a 4 pin plug with the brakes tied into the brake light circuit, the brakes would lock up every time the brakes were applied since they would apply full vehicle voltage to the brakes this way.

Since Russell rewired the trailer and now the brakes lock up when the parking lights come on it is wired wrong.

He says that with the trailer disconnected and the parking light circuit turned on he is reading 7.6 volts to the trailer brake wire. This tells me the controller he bought and had installed is wired wrong. It should not put voltage to the trailer brake wire (blue) unless truck brakes or the controller manual brake lever is applied.

If he is getting this voltage reading with the trailer wiring plug connected to the truck then trailer parking light circuit is back feeding into the controller through a crossed or wrongly wired trailer harness.

 

[Diamondpilot]

If the trailer was wired to a 4 pin plug with the brakes tied into the brake light circuit, the brakes would lock up every time the brakes were applied since they would apply full vehicle voltage to the brakes this way. Since Russell rewired the trailer and now the brakes lock up when the parking lights come on it is wired wrong.
He says that with the trailer disconnected and the parking light circuit turned on he is reading 7.6 volts to the trailer brake wire. This tells me the controller he bought and had installed is wired wrong. It should not put voltage to the trailer brake wire (blue) unless truck brakes or the controller manual brake lever is applied.
If he is getting this voltage reading with the trailer wiring plug connected to the truck then trailer parking light circuit is back feeding into the controller through a crossed or wrongly wired trailer harness.

That is what I think also George. Like I said the colors do not go red-red, black-black, ect, ect, necessarily. You have to follow the schematic. They seem to love to make things harder than they need to be. You would think they would all get together and get everyone on the same page but that would be too simple.

Chris

 

[Diamondpilot]

I just bought a used trailer, 16 ft plus 2 ft beavertail. It had a 4 wire flat connector and elect brakes wired into the brake lights. I rewired it and bought a Voyager brake controller for the 04 F150 with factory tow package and both 4 and 7 pin connectors. The problem is when setting the controller I could never lock the brakes. When driving home I turned on the parking lights and LOOK OUT, the trailer brakes locked up. I disconnected the trailer and checked the wiring on the truck side and everything looked good. I took a voltage meter to the brake controller connection and with lights off the blue wire showed 0 volts but when I turned on the lights on there was 7.6 V. How can the lights effect the brake circuit? This truck has never had a brake controller or pulled a trailer with elect brakes. HELP!!

RusseLL in Lizella, GA.

After rethinking this laying in bed, my best guess and where I would start is the wiring between the plug and controller. I believe the Voyager has 4 wires if I remember right. I have installed dozens of these in my trailer business so I am familiar but going by memory here. Anyway here is how it should be wired.


Ford Plug Controller

White Wire Black Wire
Red Wire Red Wire
Blue Wire Blue Wire
Green Wire Pink/Green/or any other Color
Black Wire Not used ------------------------------


Again this is from memory. My guess is you have the black wire of the plug going to the black wire of the controller. This black wire from the plug is for dash lights. Some controllers have dimming lights but 95% do not, only high end $400 controllers usually have them and use this 5th lead. Anyway what is happening is when you turn on the trucks lights its back feeding voltage to the brakes and locking them up.

Hope this helps. I am also PMing you my phone number if I can help any. I am by no means a expert but have wired 100's of trailers and trucks in my little marine/trailer business so I have seen lots of weird things.

Chris

 

[jones6780]

I surely hope this was my last dumb mistake for the year. I went back out today and started with the controller since I had rewired the trailer and I KNEW it was right. Well as it turns out there were two diagrams for the trailer connection plus I was looking at the slot used to index the the plug when installed. As it turned out the slot to index the plug is shown on the bottom in the diagram but on the truck it is on top. So I had wires all screwed up on the trailer side. I rewired the connector and everything works, brakes included. Thanks for all the help guys. Here are the 2 different wiring diagrams note the location of the brown wire and the index slot at the bottom. Also here is a shot of the trailer I bought cheap. $900.00 was worth it even with my wiring problems. It has 3500 lb axels and is a solid trailer. I have a 1700 Ford to haul and this will work fine for me. Thanks again.

Russell

 

[Diamondpilot]

I surely hope this was my last dumb mistake for the year. I went back out today and started with the controller since I had rewired the trailer and I KNEW it was right. Well as it turns out there were two diagrams for the trailer connection plus I was looking at the slot used to index the the plug when installed. As it turned out the slot to index the plug is shown on the bottom in the diagram but on the truck it is on top. So I had wires all screwed up on the trailer side. I rewired the connector and everything works, brakes included. Thanks for all the help guys. Here are the 2 different wiring diagrams note the location of the brown wire and the index slot at the bottom. Also here is a shot of the trailer I bought cheap. $900.00 was worth it even with my wiring problems. It has 3500 lb axels and is a solid trailer. I have a 1700 Ford to haul and this will work fine for me. Thanks again.

Russell

Glad you got it fixed. Been there done that. If there is a stupid mistake like having something out 180 degrees like you did I have done it 10 times over. My first bet was on the controller to the Ford Plug. My second bet was the wiring on the trailer. Glad it was a simple fix.

On a side note, you may want to pick up some fenders for that trailer. In my state they don't stop you for much but no fenders is one they will get you on. They are cheap, about $30 each or you can even find a fab shop to make some out of aluminum diamond plate and make them bolt on with welded on studs and wing nuts for easy removal. Could be make quick in a brake out of some scrape for under $100 around here.

Chris

 

[George2615]

I agree with Chris to get a set of fenders. Trailers in most states require them and local DOT stops will ticket you without them. Also check your tire sidewalls to make sure they say for trailer use. Its hard to tell from the pic but they look like passenger car tires which is another ticket item. Glad you got the wiring figured out. I knew it had to be something simple.

 

[Diamondpilot]

They will not get you for truck or passenger tires around here as long as you are within the load spec and they are in good shape.

They will get you for reusing mobile home axles and tires over on a trailer. They have a mileage limit stamped on them or one time use stamped on them.

Chris

 

[jones6780]

This is Georgia. I see mobile home axels on trailers all the time. I was looking at fenders. The tires are passenger tires and I will use them until they need replacing. I won't be hauling very far or heavy loads. Thanks agin for the info.

Russell