What is proper way to determine if brake controller is working? I am using a Kelsey-Hayes 81741 controller and the wiring is correct and the voltage on the wires are also ok. I am unable to determine if the trailer connector has a loose wire or not. Does anyone know if you can apply the 12 volt from a battery directly across the two wires on the trailer brake or would this cause some kind of damage. Would appreciate any info. Thanks. I am trying to rule out the wiring or connector socket before buying new controller.
trailer brakes failure
- Thread starter travel_sb
- Start date
The friendliest place on the web for anyone with an RV or an interest in RVing!
If you have answers, please help by responding to the unanswered posts.
If you have answers, please help by responding to the unanswered posts.
Alfa38User
Well-known member
- Joined
- Oct 4, 2007
- Posts
- 6,678
Yes you can. Apply the voltage with the trailer disconnected from the tow vehicle and if you do it momentarily, you should hear the brake magnets click as they energize. Wiggling the wires in the connector might help too.
It won't prove the controller but should tell you if the trailer wiring is good. Might be cheaper and quicker to just replace the connectors and try again. They are notorious for corroding and failing and it is very difficult to clean the sockets successfully.
It won't prove the controller but should tell you if the trailer wiring is good. Might be cheaper and quicker to just replace the connectors and try again. They are notorious for corroding and failing and it is very difficult to clean the sockets successfully.
COMer
Well-known member
- Joined
- Aug 25, 2009
- Posts
- 1,663
Or jack the trailer up (one side at a time) and use the brakes in the cab to see if they are energizing and how much braking you get.
Lou Schneider
Site Team
- Joined
- Mar 14, 2005
- Posts
- 13,256
The trailer brakes get full 12 volts from the trailer battery when the breakaway pin on the trailer tongue is pulled, so your first check can be to pull the breakaway pin and see if all the brake magnets work. A compass passed close to the front of each wheel will tell the tale - easier than jacking up the wheels.
This will isolate the problem connection to before or after the point where the breakaway switch ties into the brake wiring,
Don't leave the breakaway switch on for more than a minute or two, or the brake magnets will overheat - normal stopping voltage is 1/2 to 1/4 that. Same for connecting 12 volts directly to the trailer connector. If you apply 12 volts to the trailer brake wire, disconnect the controller first to prevent the voltage from backfeeding into it.
The electromagnets pull on S-cams with limited travel - you can have working magnets but no brake engagement if the brakes are out of adjustment. Unlike automobile drum brakes, trailer brakes are not self-adjusting. You have to adjust them manually using the star adjusters on the backing plates.
This will isolate the problem connection to before or after the point where the breakaway switch ties into the brake wiring,
Don't leave the breakaway switch on for more than a minute or two, or the brake magnets will overheat - normal stopping voltage is 1/2 to 1/4 that. Same for connecting 12 volts directly to the trailer connector. If you apply 12 volts to the trailer brake wire, disconnect the controller first to prevent the voltage from backfeeding into it.
The electromagnets pull on S-cams with limited travel - you can have working magnets but no brake engagement if the brakes are out of adjustment. Unlike automobile drum brakes, trailer brakes are not self-adjusting. You have to adjust them manually using the star adjusters on the backing plates.
Gord N.
Well-known member
Lou, I am having a similar problem with the brakes on my 5th wheel. I've tried to test for the magnets engaging by using the dynamite switch on the brake controller. (It is brand new). I do not hear a distinctive click sound...all I can hear is a faint hum when the controller is engaged.
Since my problem is lurching, (forward/backward) most notable when I back off power on the tow vehicle, but occasionally it will just start lurching at cruising speed too.
I've tried two different connectors on the truck(it has two), without any different result, so I suspect a short somewhere...perhaps in the trailer male connector or in the trailer wiring itself.
Would you think that the hum would indicate that the brakes are receiving power but are perhaps not releasing because of a power bleed or intermittant short, even when the controller is not being applied?
Any thoughts you might have would be helpful, I'm sure.
Gord
Since my problem is lurching, (forward/backward) most notable when I back off power on the tow vehicle, but occasionally it will just start lurching at cruising speed too.
I've tried two different connectors on the truck(it has two), without any different result, so I suspect a short somewhere...perhaps in the trailer male connector or in the trailer wiring itself.
Would you think that the hum would indicate that the brakes are receiving power but are perhaps not releasing because of a power bleed or intermittant short, even when the controller is not being applied?
Any thoughts you might have would be helpful, I'm sure.
Gord
Gord N.
Well-known member
I have had my brakes checked, wheel bearings repacked today. Still hasn't solved my "lurching" problem, but I did adjust the damping screw at the front of the 5th wheel and will test it out this weekend. Certainly seems that the road surface has alot to do with it, and I may just have to put stronger shocks on the truck to try dampening the bounce that is there.
The saga continues but eventually I will run out of options and have to just live with it! :-\
The saga continues but eventually I will run out of options and have to just live with it! :-\
Gary RV_Wizard
Site Team
By "lurch" do you mean that the hitch pin of the trailer bucks up & down? That may be a balance problem (insufficient pin weight) or a natural result of undulations in the road. The expansion strips between slabs of concrete are notorious for causing a steady lurching motion.
Gord N.
Well-known member
Thanks Gary:
No, the lurching is "front to back", however it may be our roads. We have alot of logging trucks using our highways and they tend to create pavement grooves in the road. We don't have very many concrete highways here. Most are asphalt. They get beat up pretty bad with the logging trucks and the large 18 wheelers using this section of the Trans-Canada highway. (One survey counted 629 18 wheelers passing through beside our small community over a 8 hour period.)
I have experimented with the weight(adding more to the the hitchpin by filling my water tank). No change. The weight with empty tanks is 987 lbs on the hitch which is more than 12% of the trailer GVWR. With the water in the tank I brought that to around 18% but nothing changed. The RV Mechanic said yesterday that the trailer did not require shocks, so at this point I'll believe him, although I'm not convinced.
The hitch is solid and does not appear to be bouncing. I have read on here about the "Air-Ride and similar hitch pins, and if I don't solve this I may just have to go that route. I'm going to get some advice on the benefit of beefing up my truck suspension today. I'm thinking it may keep the truck from transmitting any suspension bounce to the trailer.
Thanks for your interest.
Gord
No, the lurching is "front to back", however it may be our roads. We have alot of logging trucks using our highways and they tend to create pavement grooves in the road. We don't have very many concrete highways here. Most are asphalt. They get beat up pretty bad with the logging trucks and the large 18 wheelers using this section of the Trans-Canada highway. (One survey counted 629 18 wheelers passing through beside our small community over a 8 hour period.)
I have experimented with the weight(adding more to the the hitchpin by filling my water tank). No change. The weight with empty tanks is 987 lbs on the hitch which is more than 12% of the trailer GVWR. With the water in the tank I brought that to around 18% but nothing changed. The RV Mechanic said yesterday that the trailer did not require shocks, so at this point I'll believe him, although I'm not convinced.
The hitch is solid and does not appear to be bouncing. I have read on here about the "Air-Ride and similar hitch pins, and if I don't solve this I may just have to go that route. I'm going to get some advice on the benefit of beefing up my truck suspension today. I'm thinking it may keep the truck from transmitting any suspension bounce to the trailer.
Thanks for your interest.
Gord
Ron Buckner
Member
- Joined
- Mar 21, 2012
- Posts
- 7
Gary & Gord,
You might want to look at the wear on the magnets and the linings on the shoes. Electric brakes are no where as sophisticated as what you have in a car or truck. Basically, there is no real "graduation" with 12 v brakes. An electromagnet is on or off, when they're on they grab the armature of the drum and cock the brake shoes into the drum, and as a result the linings of the brakes shoes glaze very quickly and regardless of the current flow supplied by the controller, the "feel" of your vehicle braking will be pretty much a "clomp" and "fade" affair. Excessive wear on your magnets on one side can aid in the intensity of that initial "clomp" of the brakes engaging. This is a great topic for any of you RV inventor-types. The electric brakes of today have gone on basically unchanged since the later days of WW1 where it was discovered that a wire is a whole lot easier to fix in a battle field than a hydraulic brake line. And by WW2 our army had progressed to "moving out" at a whopping 35 MPH max. (Which incidentally is still all our brakes are rated to work at !) There is substantial room for improvement
Ron
You might want to look at the wear on the magnets and the linings on the shoes. Electric brakes are no where as sophisticated as what you have in a car or truck. Basically, there is no real "graduation" with 12 v brakes. An electromagnet is on or off, when they're on they grab the armature of the drum and cock the brake shoes into the drum, and as a result the linings of the brakes shoes glaze very quickly and regardless of the current flow supplied by the controller, the "feel" of your vehicle braking will be pretty much a "clomp" and "fade" affair. Excessive wear on your magnets on one side can aid in the intensity of that initial "clomp" of the brakes engaging. This is a great topic for any of you RV inventor-types. The electric brakes of today have gone on basically unchanged since the later days of WW1 where it was discovered that a wire is a whole lot easier to fix in a battle field than a hydraulic brake line. And by WW2 our army had progressed to "moving out" at a whopping 35 MPH max. (Which incidentally is still all our brakes are rated to work at !) There is substantial room for improvement
Ron
