Montana Brakes Not Working

[Rocketman123!]

Does anyone have suggestion about how to solve this problem? My 2022 Montana High Country fifth wheel lost its brakes about a month ago. I’ve had it to two RV dealers, one of which was a Keystone dealer, and both told me the trouble is with my 2021 Chevy 2500 diesel. Took the truck to a GM dealer and they told me the seven-way connectors on the truck are working fine and the trouble is with the camper. So... I jacked up one side, spun one of the trailer wheels, pulled the break-away-pin, and the wheel abruptly stopped spinning. Next, I replaced the 7-pin cable on the camper with a new one, but when I connected it to my truck, it was the same thing, all the lights, turn signals, etc., worked perfectly but still no electric brakes when I triggered the brakes manually with the brake controller. Anyone have an idea what’s going on here?

[scottz]

I'm not familiar with GM products, but I'd zero in on the truck brake controller. Check your truck owners manual for options.

Does your Montana have disc or drum brakes? I have disc brakes and have to set my controller to "electric over hydraulic". If I had drum brakes, it would be set to "electric".

Next step would be to make sure the controller is actually working; does it have any indications that it is working? Lights, display message, etc. If not, check fuse breaker. We need someone with a late model GM to help out.

The breakaway was a good test. That shows that your trailer brakes are working. The breakaway provides power directly to your trailer brakes without involving the truck controller.

[C&P RV]

Not a Chevy owner, but have you checked your brake controller settings in the truck? I'd start by setting the brake controller to max output, then have your spouse press the truck brakes while you measure the voltage on plug in the back of the truck with a multimeter (or you can try to turn a trailer wheel again).

[Rocketman123!]

I plugged my truck into a friend's fifth wheel and the brakes worked fine

[Rocketman123!]

I have drum brakes.

[Rocketman123!]

I'll give this a try.

[dhuhn]

Did you have your friend hitch his truck to your 5th wheel, and did your brakes work then?

[Rocketman123!]

Yes and my trailer brakes did not work. That's why we decided to swop out the 7-pin connector cable from the trailer to the truck and that did not solve the problem.

[dhuhn]

You might want to check your connection on the pin box you may have a loose wire.

[Rocketman123!]

Where's the pin box located? Is is the junction box on my fifth wheel hitch?

[mlh]

I had the same problem. The truck system worked the trailer got current to the breaks the magnets were good. Never found the problem but I took it out on the highway and applied the breaks over and over and gradually they started working until they were back to normal. Still don’t know what the problem was.
Lynwood

[dhuhn]

Originally Posted by Rocketman123!

Where's the pin box located? Is is the junction box on my fifth wheel hitch?

Yes it’s is

[scottz]

The pin box is the part that attaches to you truck. The cable that plugs into your truck (7 pin) runs up to a junction box on the pin box. Check in that junction box. Good idea Dan.

[Rocketman123!]

Thanks, I'll double check the connections we made when we installed the new 7-pin connector cable from the trailer to the truck.

[rohrmann]

Have you checked for the trailer braking fuse in the fuse box in the engine compartment? It might be at location 84. https://fuse-box.info/chevrolet/chev...ses-and-relays

[MandK]

The junction box in the pin box has the brake wire from the truck, the brake wire to the trailer brakes and the wire from the emergency brake-away spliced together. Your break away is working and your truck actuates your friends trailer brakes, so maybe the wire in your pinbox pigtail is broken or not making contact. Below is a picture I took of the brake wires from my junction box back when I installed my disc brakes. One blue is pin box pigtail, other blue is brake wire in the trailer and the black is the break-away wire that goes hot when the break-away pin is pulled. Those are the ones you’re looking for when you check your connections. If the blue from the pin box pigtail (coming from the truck) doesn’t go hot when you actuate the trailer brakes in the truck cab (by hand, not with the pedal), you need to look at the connections in the seven way plug to the trailer, double check the ground or look for a broken wire in the pigtail.

[Foldbak]

I have a 2020 GMC. If the dealer confirmed the brake controller is working at the pigtail it has to be trailer related. Your breakaway is on its on feed line. Check the connections in the giggy box. Even though the seven way brake wire goes directly to the brakes from the truck. Jumper 12 volts from the truck to the seven way and see if the breaks engage. Something tells me the dealer is foc!

[Rocketman123!]

Thanks for taking the time to take the photo. I reconnected most of these pigtails when I added the new 7-way power cable but I'll take a second look. Appreciate your help.

[Rocketman123!]

RV dealer checked and said its okay, but if problems persists I'll pull and replace it.

[BB_TX]

On your trailer cord, pin 4 is +12 v and pin 2 is brakes. Put a jumper between pin 4 and pin 2 and see if the brakes engage. That will tell if trailer wiring is good or not.