Trailer Brake Controller Wiring

[klcdenver]

I am looking for the blue wire for the electric brake controller (#7 pin) from the rear socket to where it is usually ran to under the dash or where ever. The wire must have a relay or something on it because wire tracer will not work on it. The motorhome is 2007 Moaco Diplomat 40SKQ.

Thanks,

Kenneth

[Chuck B 2004 Windsor]

I have used a wire tracer for 3 decades of telephone repairs.  I have experienced that a wire tracer will not work on an Individual wire if it has 12vdc or ground on it.  It always worked on a Pair of wires with or without 12vdc on them.

Chuck B 2004 Windsor 

[Dr4Film]

Check under the driver's side dash. There should be a complete harness there just for the Brake Controller. Hopefully it will also be labeled.

[klcdenver]

Richard,

Do you know how many wires in the harness, what gauge and if in a molex connector? It looks like a 20 year rats nest under the dash. 🥵

Kenneth

[Dr4Film]

My Tekonsha Brake Controller has a four wire harness, one wire for 12 VDC Positive, one for 12 VDC Negative, one for Brake Signal and one for Electric Brakes.

However, no clue as to what Monaco may have done. I would assume it would be a Molex Connector as that's what was commonly used throughout the coach.

[klcdenver]

Need wiring schematic for the trailer brake wiring system. I know which wires go to which pins at the bumper. I need schematic that shows relays, diodes to the fuse and into the inside under the dash etc... I am trying to find #2 (blue) wire somewhere at the front so I don't have to run new wire to the rear. It must have a relay or diode because I cannot get it to tone out with wire tracer. 2007 Diplomat 40SKQ or other Diplomats about the same year would probably be the same or similar.

Thanks,

Kenneth

[Ivylog]

A 07 should have a white plug with 5 wires… prewired for a brake controller. Hopefully it’s near the left side of the steering column as Richard posted above. Wires are R, W, Blue, Black & yellow/black and has 66 on the plug.

[Tom Cherry]

THIS is what you are looking for. Monaco added them circa 2005. THERE was an issue and the plugs were installed wrong. I THINK that Monaco corrected this in 2006.  I included the best writeup on it from the UTB site.....Universal Tow Brake actually figured it out and told Monaco where they went wrong...

Here is a link from US Gear as to the location....

http://www.usgear.cc/utbbrake_locat.htm

There will be 5 WIRES in the plug... I'm doing this from memory but I helped a lot of folks find theirs and use the wires.  I used the 3M ScotchLok connectors...

HERE is how they are connected.  They ALL will be WHITE, with some dot matrix printing on them. DIFFICULT TO READ....I toned mine out....so here goes.

BRAKE SIGNAL.  Switch must be ON, I THINK.  Think of it as the Brake Light ON switch.  It was the one that Monaco messed up.

Here is the link on HOW to fix if your brake light signal is not correct. I tried to upload my PDF but the system shot it down....

http://www.usgear.cc/utb_roadmaster.htm

Monaco messed on on the output from the service brake relay.  Will provide a 12 VDC signal.

12 VDC HOT (it is FUSED somewhere). THIS is what provides the POWER Signal that goes to an Electric Brake unit on a trailer....or on your toad's system. 

12 VDC SWITCHED....ignition switch is ON.

Ground

WIRE TO REAR of trailer connector. This is the INFAMOUS BLUE WIRE. It will have NO VOLTAGE.  It will have NO CONTINUITY to GROUND.  It is just a plain connector going to the rear.  It DOES NOT run through any relay or such.....think a SPARE wire to the rear.  It will be an OPEN circuit when you check it at the FRONT on the Molex connector....

Use your VOM and locate the first FOUR. Once you have established them.....  THEN you can do ONE of two things....  I ran a 50 ft piece of #20 Hookup WIRE and then used my VOM to the rear.  BINGO...it worked.  Others have done it differently.....GRound to chassis or use a 9 VDC battery and go to GROUND with one side....

 

Good luck...

[klcdenver]

21 minutes ago, Tom Cherry said:

THIS is what you are looking for. Monaco added them circa 2005. THERE was an issue and the plugs were installed wrong. I THINK that Monaco corrected this in 2006.  I included the best writeup on it from the UTB site.....Universal Tow Brake actually figured it out and told Monaco where they went wrong...

Here is a link from US Gear as to the location....

http://www.usgear.cc/utbbrake_locat.htm

There will be 5 WIRES in the plug... I'm doing this from memory but I helped a lot of folks find theirs and use the wires.  I used the 3M ScotchLok connectors...

HERE is how they are connected.  They ALL will be WHITE, with some dot matrix printing on them. DIFFICULT TO READ....I toned mine out....so here goes.

BRAKE SIGNAL.  Switch must be ON, I THINK.  Think of it as the Brake Light ON switch.  It was the one that Monaco messed up.

Here is the link on HOW to fix if your brake light signal is not correct. I tried to upload my PDF but the system shot it down....

http://www.usgear.cc/utb_roadmaster.htm

Monaco messed on on the output from the service brake relay.  Will provide a 12 VDC signal.

12 VDC HOT (it is FUSED somewhere). THIS is what provides the POWER Signal that goes to an Electric Brake unit on a trailer....or on your toad's system. 

12 VDC SWITCHED....ignition switch is ON.

Ground

WIRE TO REAR of trailer connector. This is the INFAMOUS BLUE WIRE. It will have NO VOLTAGE.  It will have NO CONTINUITY to GROUND.  It is just a plain connector going to the rear.  It DOES NOT run through any relay or such.....think a SPARE wire to the rear.  It will be an OPEN circuit when you check it at the FRONT on the Molex connector....

Use your VOM and locate the first FOUR. Once you have established them.....  THEN you can do ONE of two things....  I ran a 50 ft piece of #20 Hookup WIRE and then used my VOM to the rear.  BINGO...it worked.  Others have done it differently.....GRound to chassis or use a 9 VDC battery and go to GROUND with one side....

 

Good luck...

Thanks. I found a molex in that position but it has 6 wires in it. I will have to check it out again. Hopefully it will tone out. If not I have about decided to try the Curt RF wireless system. I found 2 other molex connectors under the dash but do not tone out to the blue wire on the rear plug.

[Dr4Film]

The Electric Brake Wire should be a heavier gauge wire and therefore much thicker as it has to carry more amps than the other wires needed for the brake controller.

[Ivylog]

14 hours ago, Dr4Film said:

The Electric Brake Wire should be a heavier gauge wire and therefore much thicker as it has to carry more amps than the other wires needed for the brake controller.

Thicker than the Red and Black?

[dl_racing427]

14 hours ago, Dr4Film said:

The Electric Brake Wire should be a heavier gauge wire and therefore much thicker as it has to carry more amps than the other wires needed for the brake controller.

Actually, the Red wire should be as large as the blue, as it supplies power to the whole system.

[klcdenver]

Does anyone know where the 12 volt power source for the center connector on the trailer plug starts and where the fuse is located?

Thanks

[Chuck B 2004 Windsor]

On the 2004 Windsor the 12 vdc comes from the black box number one located in the front run bay.  Chuck B 2004 Windsor

[Tom Cherry]

On 9/13/2021 at 9:39 AM, klcdenver said:

Does anyone know where the 12 volt power source for the center connector on the trailer plug starts and where the fuse is located?

Thanks

On the Camelots.....  There is a Relay that controls it.  The relay is activated or triggered by the Ignition ON circuit. The relay then gets FUSED power...from the Chassis Battery Buss....  The relay and the fuse are in the back or somewhere in the REAR Run area. When the switch is ON, then the relay is closed and you get charging current for the Toad's batteries or a braking system. I have never had to locate the relay.

Here is the schematic for the Camelot Rear Trailer plug.....plus the SUPPOSED color codes...Trailer Plug.pdfTrailer Plug.pdfTrailer Plug.pdf

Here is a link to the print....this works, I think for 2006 - 2008.... Diplomats

https://www.irv2.com/forums/attachment.php?attachmentid=153030&d=1488076011

Go to this forum and you will find your answer....it specifically addresses it....

https://www.irv2.com/forums/f115/trailer-harness-fuse-location-328460.html

You should be good to go.....now you know....

  

[klcdenver]

Thanks . Good info. I found the fuse blowed in the rear panel yesterday for the trailer charging. Never found the wire for the electric brake controller under the dash or side panel. I gave up and just ordered a Curt Echo RF wireless brake controller. 

[Tom Cherry]

On 9/18/2021 at 1:04 PM, klcdenver said:

Thanks . Good info. I found the fuse blowed in the rear panel yesterday for the trailer charging. Never found the wire for the electric brake controller under the dash or side panel. I gave up and just ordered a Curt Echo RF wireless brake controller. 

There is a 5 wire pigtail with a 6 pin Molex connector under or behind the driver's left console or the "box" where all the switches are....OR it is pulled up under the left side of the steering column OR it is pulled up and is behind the dash.  Monaco put it in there.  You just have to find it.  There is NO BLUE WIRE up there.  It is part of the five white wires....and you would need the print (which I had but is in my MH now) that shows the connections).  

There may be several Molex connectors with nothing attached to them...but I THINK that the 6 wire pin is the only one of it's design...

TRUST ME....it is there.....many folks have had to look several times as Monaco put it whereever they wanted to. 

You MIGHT have to "FEEL" up inside, towards the top of the driver's console. For example, mine was buried on the floor in the middle of the console.  On another Camelot, the harness was pulled up on the dash side and was accessibe from the opening in the dash and was sort of "behind" the headlight switch...

 

[Rodger]

My 2004 Endeavor did not have a trailer brake wire in the rear plug. There were 6 wires; left/right turn signals, ground, brake light, reverse light, and power. No brake wire. I had to run one from one end to the other. That is quite a task. On my old Tiffin gas burner I was able to run inside the frame, but on these it is impossible to do so due to the construction of the bottom storage. I was able to run a wire along the passenger side engine, to the LP gas area, crossed to the left side at the water/sewer area, then along the upper inside edge of the storage, thru the upper fuel door area, then back toward the center along other harnesses and then thru the front fire wall. Picked up power and the signal from the brake light relay in the lower power panel and ran in the firewall with the brake wire. Seems to work fine after that ordeal.