Trailer Brake Controller Wiring

[-twitch-]

I hooked up my brake controller as stated below and it is telling me there is no trailer attached when everything is plugged in.


This how the brake controller and chassis are labeled:

Ford Chassis
Brown – Illumnation
Dark Blue - Trailer Brake Feed
Red – Brake Controller Feed
White – Ground
LT Green – Stop Lamp Feed to Brake Controller


Brake Controller (Prodigy P3)
Blue – Brake
White – Ground
Red – Stop Light
Black – Battery


This is how I hooked it up:

Brake Controller | Ford Chassis

Blue – Brake | Dark Blue - Trailer Brake Feed
White – Ground | White – Ground
Black – Battery | Red – Brake Controller Feed
Red – Stop Light | LT Green – Stop Lamp Feed to Brake Controller

I capped the “Brown – Illumination” on the Ford Chassis

SIDE NOTE: This is how I have it hooked up in the rear...


When I bought the RV he had a plug like this…




So I bought this so I would not have to mess with any of the wiring.



I have not checked any of the wiring in the rear yet. I figured I would start in the front were I made the connections.


Thank you for the help

[Scarab0088]

Could be 1 of 2 problems.
1. The trailer plugs are not configured correctly (see the diagram at the bottom) or
2. The feeds to the P3 are the problem.

To double check the wiring, you will need to actually test the wires (requires volt meter or 12volt test light and continuity gauge).

The feed to the Brake control has to include:
1. 12volt thru a fuse to the Black wire
2. White to a good ground
3. A straight feed from the brake light activation switch of the chassis to the P3's red lead (cannot be one of the exisiting brake light (brake and turn signal) feeds.
4. Blue to the trailer brake wire going to back plug.

See more here: How to Wire a Tekonsha P3 | eHow.com

Your description for the P3 connections is correct but the terms "Stop Light" and "Brake" are what I would check first:

Here is a wiring diagram for the plugs:


Best of luck!

[v8dave]

What year and model is your Ford truck? You may already have a trailer brake controller connector buried somewhere in the dash wiring harness. In my 2003 F250 there was one that needed an adapter to connect to the trailer connector.

In my 2011 Nissan Frontier there is a connector (which needs an adapter) for a brake controller, even though it isn't rated for a trailer that would need brakes.

I agree with Steve's comments above, you need to tap into the brake switch circuit, not the brake/turn signal light. Not the least of which you may get strange braking behavior when the the turn signal starts working and you are asking for brakes on the trailer.

[-twitch-]

Originally Posted by v8dave

What year and model is your Ford truck? You may already have a trailer brake controller connector buried somewhere in the dash wiring harness. In my 2003 F250 there was one that needed an adapter to connect to the trailer connector.

In my 2011 Nissan Frontier there is a connector (which needs an adapter) for a brake controller, even though it isn't rated for a trailer that would need brakes.

I agree with Steve's comments above, you need to tap into the brake switch circuit, not the brake/turn signal light. Not the least of which you may get strange braking behavior when the the turn signal starts working and you are asking for brakes on the trailer.

Sorry I wasn't more clear. The Ford Chassis is under my Class A

[v8dave]

twitch, you need to do the checking and testing that Steve suggests.

You need to identify what is on each of the wires coming from the chassis before using them. It looks like you are currently using the wrong wire to connect to the Trailer Brake Controller's red wire. The link Steve supplied will help you find the correct wire.

[Hikerdogs]

You said you didn't mess with any of the wiring at the rear, which is where I believe your problem lies.

When the Ford F53 chassis are sent to the coach builders the wires for the trailer socket are folded back in the loom and taped off. Ford does not install the trailer socket on the rear of the frame when it's shipped. In many cases the coach builders extend the frame then install the trailer socket and extend the wires.

For some reason most coach builders leave the blue #10 brake wire in the loom at the end of the original frame member and only extend the wires for the lights. Before tearing everything apart follow the wiring harness from the trailer socket back to the frame. There should be a set of connections inside the loom at the end of the original frame member (not the frame extensions installled by the coach builder) on the drivers side. In all likelyhood the #10 blue wire was never extended to the trailer plug and is is still folded back and taped off at that junction.

To further complicate things I believe your chassis is equipped with a brake controller plug under the dash. It isn't the same configuration as the plug on the controller. You have to buy a product specific (Ford, Workhorse, Freightliner, etc) jumper harness.

It took a while to find the plug under the dash on our Ford chassis. It was taped to the steering column. I would have never recognized it if I hadn't had the jumper harness in hand. It took longer to find the wire folded back at the rear of the coach than it did to find the plug in the front and install the controller. I had to add about 6 feet of #10 wire to run it through the harnesses and connect it the the socket.

[-twitch-]

Originally Posted by v8dave

twitch, you need to do the checking and testing that Steve suggests.

You need to identify what is on each of the wires coming from the chassis before using them. It looks like you are currently using the wrong wire to connect to the Trailer Brake Controller's red wire. The link Steve supplied will help you find the correct wire.

The wires were identified by a tag that was attached to the wires on the chassis.

I checked the wires Steve mentioned and everything is connected correctly. At least I think (did I mention I suck\hate electrical)

I guess I will start playing with the plugs in the back of the RV

[-twitch-]

Originally Posted by Hikerdogs

You said you didn't mess with any of the wiring at the rear, which is where I believe your problem lies.

When the Ford F53 chassis are sent to the coach builders the wires for the trailer socket are folded back in the loom and taped off. Ford does not install the trailer socket on the rear of the frame when it's shipped. In many cases the coach builders extend the frame then install the trailer socket and extend the wires.

For some reason most coach builders leave the blue #10 brake wire in the loom at the end of the original frame member and only extend the wires for the lights. Before tearing everything apart follow the wiring harness from the trailer socket back to the frame. There should be a set of connections inside the loom at the end of the original frame member (not the frame extensions installled by the coach builder) on the drivers side. In all likelyhood the #10 blue wire was never extended to the trailer plug and is is still folded back and taped off at that junction.

To further complicate things I believe your chassis is equipped with a brake controller plug under the dash. It isn't the same configuration as the plug on the controller. You have to buy a product specific (Ford, Workhorse, Freightliner, etc) jumper harness.

It took a while to find the plug under the dash on our Ford chassis. It was taped to the steering column. I would have never recognized it if I hadn't had the jumper harness in hand. It took longer to find the wire folded back at the rear of the coach than it did to find the plug in the front and install the controller. I had to add about 6 feet of #10 wire to run it through the harnesses and connect it the the socket.

I will check this.

I found the wires tucked under the dash and wired them to my "p3" luckily I found them pretty easy.

If the previous owner was flat towing a vehicle, would the blue wire been used?

[Hikerdogs]

Originally Posted by -twitch-

I will check this.

I found the wires tucked under the dash and wired them to my "p3" luckily I found them pretty easy.

If the previous owner was flat towing a vehicle, would the blue wire been used?

.
The light blue #10 wire only supplies voltage for electric brakes. If the previous owner was flat towing a vehicle it would not have been used. They probably didn't even know it existed

[-twitch-]

**** UPDATE ****

THe wiring in the back was not correct for towing a trailer. I was able to find 6 of the 7 wires i needed to hook up my 7 blade connector.

The only wire I am missing is the Power\12V. Is there a 12v wire pre wired in and I am missing it or do I need to wire my own in?

[Hikerdogs]

The 12volt power wire for the brakes should be in the original Ford harness. It's a large (#10) blue wire. Remember Ford only extends the wires to the rear of the original frame, not the frame extensions. At that point all the wires are labeled, taped off, and folded back into the wire loom. There's usually about 16" - 18" of wire folded back.

Follow the wires you've found back to the point where they're spliced into the original harness. Then open the original harness and start searching toward the front of the coach. The body builder may have pulled it further forward into the harness and taped it off so only the wires they wanted connected were exposed.

Sometimes the entire group of wires is wrapped with black electrical tape before it's inserted in the loom. That makes it extremely difficult to determine where 1 wire stops. If you can't find the blue wire near the end of the original frame rail (outside drivers side) follow the loom forward a few feet and open it again. This wire has come as standard equipment at least as far back as 1999. It's difficult to find since there is nothing in the harness to keep the wires organized. It can be wound or twisted around making it invisible in one place but obvious in another.

[-twitch-]

Originally Posted by Hikerdogs

The 12volt power wire for the brakes should be in the original Ford harness. It's a large (#10) blue wire. Remember Ford only extends the wires to the rear of the original frame, not the frame extensions. At that point all the wires are labeled, taped off, and folded back into the wire loom. There's usually about 16" - 18" of wire folded back.

Follow the wires you've found back to the point where they're spliced into the original harness. Then open the original harness and start searching toward the front of the coach. The body builder may have pulled it further forward into the harness and taped it off so only the wires they wanted connected were exposed.

Sometimes the entire group of wires is wrapped with black electrical tape before it's inserted in the loom. That makes it extremely difficult to determine where 1 wire stops. If you can't find the blue wire near the end of the original frame rail (outside drivers side) follow the loom forward a few feet and open it again. This wire has come as standard equipment at least as far back as 1999. It's difficult to find since there is nothing in the harness to keep the wires organized. It can be wound or twisted around making it invisible in one place but obvious in another.

I found the wires that all stop at the frame as you mentioned. There is about 10 of them. The blue wire was labeled "electronic trailer brake". I only see two large #10 wires coming from the RV one is white and labeled ground and the other is White\Red (this was the only wire that was not labeled out of the whole bunch) and I checked it and it is not hot even with the RV running.

Please note that some one before me had wired in a 5 pin connector for a TOAD

[Hikerdogs]

The red/white wire may be for the backup lights. I have a CD version of the Ford factory repair manual. I'll see if I can find a schematic with the wire colors for the trailer wiring harness.

Unfortunately the RV is in storage so I can't look at the actual wiring harness.

[grtharris]

-twitch- for some reason unbeknownst to me Ford does not include the +12V power wire in the trailer wiring. See the attached drawings.
Winnebago on 1999 and newer adds the +12V wire from there own breaker panel.