Brakes not working - is it truck or trailer

[joebedford]

My 2011 Voltage 3950 and Silverado 3500HD brakes have worked fine for 4 years. Now I'm on a trip to Texas and I have no trailer brakes. I'm trying to figure out if the truck's brake controller has croaked or if I have a problem in the trailer.

I've done all the usual stuff checking connections, cable continuity, etc.

The only reading I get that may be wrong is the total resistance between brake leads at the 5er junction box. I read 3.3 ohms. That seems to be quite high for a tri-axle.

What does your 5er read?

[MartyG]

Forget continuity checks. Check voltage on the brake power lead with the truck engine on, and someone stepping on the brake. It should be a positive voltage, more than zero, but less than 13. It should go back to zero when the foot is off of the pedal. If so, the controller and truck wiring are working. If not, it's one of them.

[hddecker]

How long has it been since you have adjusted the brakes? Electric trailer brakes are notorious for going out of adjustment fairly fast. I was adjusting mine every 3-5K, closer to the 3K mark when we went to Alaska.

This is the reason I converted to disk brakes, no more adjusting while we are travelling.

Can you lock up the wheels if you hold the manual slide on your controller to the max. If you can't your brakes probably need adjusting.

[joebedford]

Brakews adjusted 2K ago. It's not mechanical.

Problem is, 'smart' brake controller needs to detect the trailer before it puts a voltage on the brake line. It isn't seeing the trailer. No way to tell from the test Marty suggested if that is the truck or the trailer causing the problem.

[hddecker]

Originally Posted by MartyG

Forget continuity checks. Check voltage on the brake power lead with the truck engine on, and someone stepping on the brake. It should be a positive voltage, more than zero, but less than 13. It should go back to zero when the foot is off of the pedal. If so, the controller and truck wiring are working. If not, it's one of them.

Forgot the voltage is first the first thing to check.

I should have remembered that from trouble shooting my disk brake install.

[hddecker]

Originally Posted by joebedford

Brakews adjusted 2K ago. It's not mechanical.

Problem is, 'smart' brake controller needs to detect the trailer before it puts a voltage on the brake line. It isn't seeing the trailer. No way to tell from the test Marty suggested if that is the truck or the trailer causing the problem.

Which controller are you using? Does cranking the booster to the max do anything?

Voltage test is still the place to start, it will tell you if the controller is sending a signal. If you have voltage at the trailer, you definately know the problem is between the connector and the brakes.

A very quick way to tell if your brakes are activating is to pull the pin on the breakaway switch. If the Brakes a working, they should lock up.

[MartyG]

While placing wheel chocks recently, my daughter heard a hum/buzz from our brakes. (Because I had my foot on the pedal) Maybe if you pulled the breakaway pin as suggested, you might hear such a noise.

[joebedford]

Problem solved. I got a guy with a truck like mine to plug into our rig and there was no connection. I plugged his rig into my truck and the truck registered the connection immediately.


So under the trailer I went and found 3 brake wires severed. I must have hit some debris on the road that cut these wires - they were cut on the driver's side in the area where they don't have to flex.


I have brakes again. YAY!


For the record, I get 1.2 ohms on the brake lead now.

[MartyG]

Glad it was that simple! Good news!

[hddecker]

That's great!

[chily3]

Good news

[gwcamp]

You are to have a 2-3 amp draw from each wheel. I use a car dash amp gauge from nappa and run power threw gauge to pig tail on positive side and have a ground wire from a 12 volt batt.You can get under trailer and listen to magnets hum.That's a way also to tell if brakes are working.

[Occupant5143]

Originally Posted by joebedford

So under the trailer I went and found 3 brake wires severed. I must have hit some debris on the road that cut these wires - they were cut on the driver's side in the area where they don't have to flex.

Kinda scary to think that it can happen like that on the road.

[DENNY]

I have a 2017 Chevy. 3500 truck and a 2017 3605 Voltage camper. While driving my truck , the info. center said check the trailer brake system. When I pulled the pin for the brakeaway switch the switch started smoking and the wires got hot. I first told my Chevy Dealer and they told me the problem was in the trailer. I told my trailer dealer and they told me the problem is in the truck. I am a Auto Tech by trade, is anyone having this problem. Thanks Denny

[pdonoghu]

I had intermittent loss of brakes according to my F350’s control center. The truck has an integrated brake controller. I had the Ford dealer trouble shoot, and they said everything was OK, must be the trailer. They said if the trailer brakes drew over a certain amperage, the Ford controller would turn off. Took the trailer into the RV dealer, they found weak magnets, & checked the wiring. New electric brakes, and almost 2,000 miles latter, no problems.

Did you disconnect the truck when you pulled the pin? If so, it has to be the trailer. The switch smoking and heating up tells you it carrying too much current. I’d replace the switch, and check the wiring & each wheel for shorts. How old is the trailer? The clips that hold the brake magnet wire are notorious for falling off, and the wire gets shorted, or the clips were never installed.

[sundancer 87]

Originally Posted by DENNY

I have a 2017 Chevy. 3500 truck and a 2017 3605 Voltage camper. While driving my truck , the info. center said check the trailer brake system. When I pulled the pin for the brakeaway switch the switch started smoking and the wires got hot. I first told my Chevy Dealer and they told me the problem was in the trailer. I told my trailer dealer and they told me the problem is in the truck. I am a Auto Tech by trade, is anyone having this problem. Thanks Denny

Is anyone having this problem? You mean with the dealer not wanting to stand behind its product? Absolutely, deaf dealers are everywhere. The RV is still under warranty, stay on them to get the problem resolved. They can't troubleshoot or diagnose a problem from a narrative, especially RV people.