We have a 2009 Mandalay 43A, and I need to install a trailer brake controller. The rear of the coach has a seven-pin connector, but there's no controller up front. I realize unless you have the same coach you won't know exactly, but is it customary for the manufacturer to pre-wire for the controller? Is there a special code for wire colors that could help with my search? The owner's manual is virtually worthless.I'm sure most of you have owned your class A's for a while and I'm leaning on you and your knowledge.Many thanks in advance,Pat in Menifee, CAwww.patcarnathan.com

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.

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.

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.

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.

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.

Class A DP Trailer Brake Controller Wiring | Good Sam Community

19 Replies

Big_Katuna
Explorer II
Mar 17, 2015
I bought an inertial sensing controller; no wire from the brakes lights required. Works great, very adjustable.

Under my dash, the excess loom was bunched together and bundled with lots of ty wraps. I had to cut all the ty wraps apart to find the brake harness. I also took the idiot light panel out and laid it on the dash which gave me much better access to the under dash wire harnesses.

I never would have found it by just looking up from the floor.
bigdisplay
Explorer
Mar 17, 2015
PCarnathan wrote:
Still no luck. We spent an hour looking under, over and around the dashboard to no avail. Tekonsha sent me some pictures of the plug and specific wiring instructions, but if I can't find the wiring I'm still stuck. As for actuating the controller with air brakes - Even air brakes activate brake lights; and that's how the controller receives the signal.

The search will continue. Thanks for the answers and suggestions.

Pat in Menifee, CA
www.patcarnathan.com

DID??? you look at the 7 pole connector and make sure you have the Blue brake lite wire????????
If its factory wired you will have a Blue wire for the brakes, red or black for the charge,white for grounds,BRown for tail/run,yellow/green for turn/brake lites and another wire if Back up lites are prewired. so SIX or SEVEN wires go look
bigdisplay
Explorer
Mar 17, 2015
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.

Most likely the factory wires are there for towing
Hooking the controller to the brake lite sensor is same as brake lite switch
As far as the exhaust brake goes how would it come on?

BUT If you have a trailer heavy enough you need electric brakes then there is no way a little exhaust brake will be sufficient to not only hold back the MH on a steep decline but the loaded trailer also
PCarnathan
Explorer
Mar 17, 2015
Still no luck. We spent an hour looking under, over and around the dashboard to no avail. Tekonsha sent me some pictures of the plug and specific wiring instructions, but if I can't find the wiring I'm still stuck. As for actuating the controller with air brakes - Even air brakes activate brake lights; and that's how the controller receives the signal.

The search will continue. Thanks for the answers and suggestions.

Pat in Menifee, CA
www.patcarnathan.com
DSDP_Don
Explorer
Feb 21, 2015
Big Katuna.....I realize that, installing the controller is the simple part, it's locating or installing the trip wire on a DP that is a PITA.
Big_Katuna
Explorer II
Feb 21, 2015
Gas or diesel you still need a controller.
DSDP_Don
Explorer
Feb 21, 2015
Gasman2....no problem....you would think the chassis manufacturers would just incorporate the trigger wire that wasn't affected by the exhaust brake. Our neighbor had a prewired Monaco. The trigger wire didn't work and the wire that was suppose to run the length of the coach didn't work....a known problem. It's so much easier with a gas coach!
pigman1
Explorer
Feb 21, 2015
If you have a Freightliner chassis, it's pre-wired under the dash. I have a PDF that I got at Camp Freightliner, but I don't know how to attach it to these posts. There's a 6 pin connector with only 5 wires in it and the PDF gives wire sizes and colors to look for. If you PM me an email address I'd be happy to mail it to you. On my 2008 Tiffin the Tiffin factory used that plug to power other things under the dash, but the wires were all there and all worked.
Gasman_2
Explorer
Feb 21, 2015
DSDP Don wrote:
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.

Don sorry,
It sounded like in were talking about something other than the brake light
switch.
Big_Katuna
Explorer II
Feb 20, 2015
My 05 Freightliner was prewired. If there is a wire in the rear connector, yours probably is too.
My connector was buried in the bundle of wires by the steering column.

As stated it was in a square white connector.

There are inertial sensing controllers that worked very well.

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Class A DP Trailer Brake Controller Wiring

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