2023 Coachmen 27QB Brake Controller Wiring

[2023coachmen27qb]

We just purchased a new 2023 Coachmen Class C 27QB with the new Chevy 6.6L gas engine. The chassis is a 2022 model year based on the Chevy 3500 cutaway. The coach came with an 8600# rated trailer hitch that has the 7-way and 4-way connectors wired to the back. I have owned a 3500 Express passenger van and was able to connect my Hopkins brake controller to a 4-wire loom that GM included. The harness included with this class C is taped up under the driver's side under upper left dash but is a 5 wire with no wiring diagram to follow. The color scheme is completely different than any GM brake control harness I have ever seen before.

Does anyone know how to connect this 5 wire harness to a standard 4 wire brake controller? I have asked Coachmen and General RV. Still waiting for their response. I am going to use my 12v test light to see which of the wires powers the brake controller. Not sure how to determine the other 4. Also will compare the color and size of wires going back to the 7-way connector.

[TimLG]

I have a 2019 27QB on Chevy Express 4500 chassis. I’m using the 7-pin connector that is connected to 6-pin connector on my 4500 lbs. toad. I had to add 2 wires to the 7 pin for:
12 volt supply to charge toad battery when towing
“Brakes On” LED indicator from brake controller that I mounted on corner of dash.

I connected those 2 wires at the harness you referenced tucked under the drivers side mat, and ran a 2 conductor SO cord along the frame. I found a wiring diagram on line but used a volt meter to ID the correct circuits.

I recommend checking your combined cargo capacity for the max weight of your trailer or toad. I weighed our rig, 10,500 lbs. partially loaded. I can add ~3000 lbs of weight in cargo and fluids and stay under the 20,000 lbs CCC.

[BehindBars]

Originally Posted by TimLG

I have a 2019 27QB on Chevy Express 4500 chassis. I’m using the 7-pin connector that is connected to 6-pin connector on my 4500 lbs. toad. I had to add 2 wires to the 7 pin for:
12 volt supply to charge toad battery when towing
“Brakes On” LED indicator from brake controller that I mounted on corner of dash.

I connected those 2 wires at the harness you referenced tucked under the drivers side mat, and ran a 2 conductor SO cord along the frame. I found a wiring diagram on line but used a volt meter to ID the correct circuits.

I recommend checking your combined cargo capacity for the max weight of your trailer or toad. I weighed our rig, 10,500 lbs. partially loaded. I can add ~3000 lbs of weight in cargo and fluids and stay under the 20,000 lbs CCC.

I think you are confused on the terms. Did you mean to say stay under the 20,000 lbs GCWR (Gross Combined Weight Rating)? CCC is the Cargo Carrying Capacity of the motorhome itself, not "combined cargo capacity", and has nothing to do with the trailer or toad, except that the tongue weight placed on the motorhome hitch would be part of the motorhome's cargo. CCC certainly wouldn't be 20,000 pounds on a Chevy 4500 based motorhome. As you suggest, in your case CCC is more on the order of 3000 lbs. GCWR is set by the chassis manufacturer and is the maximum combined weight rating for the motorhome and trailer or toad.

[2023coachmen27qb]

Thank you for the reply. In my case i will not being towing a vehicle with 4 wheels on the ground but may pull a tow dolly that has electric brakes. So i need to have the 7 pin connector at the rear of the motorhome wired to a standard brake controller. I check to see that the 7-pin that Coachmen installed at the factory was actually wired in and it is. Now just waiting on Coachmen to tell me what the wiring under the dash that they installed at the factory. The color code is not the same as at the rear of the coach. I will probably just be using my volt meter and test light to match up the front to the back.