Class A DP Trailer Brake Controller Wiring

I believe your Mandalay is equipped with a raised rail Freightliner chassis, and it will be pre-wired for a "trailer brake" which is indeed the same wiring required for a toad braking system controller.

Typically, it is a six pin flat connector with four wires attached to it and a protective cap on it. Usually you will find it under the dash to the left of the steering wheel...sometimes it is located in the driver's left console. If it has not been previously used (sounds like you are not the original owner), it may be tied up with other wiring harnesses and very difficult to find. I located mine by finding the wiring harness coming out from the steering column and then following it for about six inches until I found the first harness leading off of the steering column harness. At the end of that harness was the connector. It was up under the dash just as far as possible and tied to another harness. I had a hard time cutting the ties so that I could get the connector and it's harness back down to where I could access it.

However, you will probably need an adapter cable from the manufacture of the controller (or toad brake system) that will mate the mh's connector with the controller's connector.

Good luck

Ron

Gasman2....I don't get what you're asking...you stated the same thing as I did, except I didn't add the word "air" in my sensor statement.

Yup, it sucks but is what it is. I guess they figure people with a big DP won't be towing anything. WRONG!!!!

glamisorbust wrote:
I just went through all of this myself. I have a 1999 holiday rambler endeavor diesel pusher. It did not come with the required wiring for brake controller. It was not pre-wired whatsoever. I had to wire the entire thing myself, which was quite a bit of work.

I had to run two wires from the front of the dash, through the firewall, and down the entire frame rail. It was a pain in the rear. I also had to find a power source up front for the controller and install a 7 pin connector out back. It was a big job but it's done now and I have been towing my big trailer trouble free.

My advice is to call the manufacturer that built the RV and get a tech on the phone. That's what I did, and they were able to tell me that my coach did not come with any trailer brake wiring.

Some of them come pre-wired and are labeled. They would be able to tell you exactly where the wires are located, if they are there.

Odd how a coach can cost $100k+ new and it gets skimped on $10 worth of wire even though it's wired for a trailer.

One way to find out is to put a tone on the BRAKE contact on the rear connector and then sniff around inside the dash.

Just search for a Fox and Hound. Some are very reasonable and incredibly valuable when trying to find that elusive blown fuse or wire.

In any case, remove the dash instruments if possible and use a strong light to look for wires. On some RV's the wires may be the same color and actually have the function printed on the side of the wire. They can be cryptic. That current of a model probably has the wire already run.

DSDP Don wrote:
If you're prewired, the loom will USUALLY consist of four wires, similar in color to the wires on your controller.

The issue with DP's is that they don't use a brake switch which triggers the braking system. They use pressure sensors on the firewall. You need something to trigger the system and make sure it doesn't come on with the exhaust/engine brake.

Explain what these sensors are if there are not the brake light switch. Air brake systems usually use a brake light switch that activated by air pressure when you apply the brakes. Most systems will use two switches that preform the same task.
Not hard to find as they are on or near the brake valve.

Unlike most PU's in the last 15 years where you just hook up the controller to the pigtail for it, very few MH's do the same. There is a good possibility that there are spare wires running to the back so call and ask your tech support.
Monaco does this but finding them can take some searching. Even though I knew to look for a six wire plug (knew the color of the wires) it took several tries to find it high up in the dash just left of center. Then I had to find them in the front run box so I did not have to route two new wires for power and the brake signal from the air brakes.

If you're prewired, the loom will USUALLY consist of four wires, similar in color to the wires on your controller.

The issue with DP's is that they don't use a brake switch which triggers the braking system. They use pressure sensors on the firewall. You need something to trigger the system and make sure it doesn't come on with the exhaust/engine brake.

I just went through all of this myself. I have a 1999 holiday rambler endeavor diesel pusher. It did not come with the required wiring for brake controller. It was not pre-wired whatsoever. I had to wire the entire thing myself, which was quite a bit of work.

I had to run two wires from the front of the dash, through the firewall, and down the entire frame rail. It was a pain in the rear. I also had to find a power source up front for the controller and install a 7 pin connector out back. It was a big job but it's done now and I have been towing my big trailer trouble free.

My advice is to call the manufacturer that built the RV and get a tech on the phone. That's what I did, and they were able to tell me that my coach did not come with any trailer brake wiring.

Some of them come pre-wired and are labeled. They would be able to tell you exactly where the wires are located, if they are there.