RickyD32
Essex Jct., Vermont
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Joined: 07/18/2008
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So this is where I'm at now. I did get the meter out and I had 12 volts at the plug for most things. The blue wire onlt read 8 volts at the plug on the TV but that is what my controller is set at for output. I assumed this was correct. So I got under the RV and opened the box with all the wires going into it. What I found was interesting. There are three wires connected together, A blue wire (for the breaks) and two black wires. One is for the break away and the other went back to the breaks in the back of the RV. The meter would not ready anything when I tested these three wires all together. So I pulled them apart and tested the blue wire and all of a sudden I had the 8 volts I was getting at the plug (this is with the break controller activated). I put the blue wire and the black wire from the break away back together and rechecked with the meeter, I still had 8 volts. When I put the third wire (the one that goes ba ck to the breaks) I again had zero at the meter. This wire runs in a harness with one black wire and one white wire. The white does have a good ground. I am thinking that the wire that runs to the back breaks has to be the problem I went to the back axles and checked the wires there. I found the first set of wire nuts on the first wheel to appear to be slighted melted. I cut the wires and spliced them together but that did not fix the problem. The wires going thru the axles seem ok from what I can see. I am hoping the problem is not the magnets or inside the breaks. As you know it's a lot of work to get to them. So I will ask you, what would you think this would be? Does it sound like I am on the right track?
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TnTtravelers
East Slope Sierra, California, USA
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When you say you don't have brakes, do you mean while going down the road, or while not moving. I think that some designs use a brake system that works on centrifigul force, where they only engage while moving down the road when you step on the brake pedlem or actuate the controler manually. But only when moving.
Someone correct me if I am wrong, but me thinks this is true.
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thomasinnv
where ever i stop
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even the centrifugal ones apply a small amount of braking power when not moving. you should be able to disconnect all the brake wires at each individual wheel, then connect one at a time untill you find one that is the problem. if you manually activate the controller using the slide control or button, you should get the full 12 volts, if not you may have a problem with the controller. when manually activating the controller to maximum braking, you should be able to hear the magnets hum.
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Deen
Vancouver, WA
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Hmm.. your brakes are broken?
The brake controller sends electricity to an electromagnet in the drum, the shoes are activated by the magnetic pull against the inside of the drum as it rotates. So there isn't much braking force at rest but you can hear the electromagnets engage if they're working correctly.
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fla-gypsy
North Florida
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If you are sure your controller is good I would check the break-away switch. I recently had a short circuit that was originating inside mine. I pulled the plunger out and shoved it back in and it went away. While it was causing the short (it was intermitent at first) I had no trailer brakes and it took me a while to figure it out. Good luck.
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Vulcanmars
Naples, FL
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RickyD32 wrote: I found the first set of wire nuts on the first wheel to appear to be slighted melted. I cut the wires and spliced them together but that did not fix the problem. The wires going thru the axles seem ok from what I can see. I am hoping the problem is not the magnets or inside the breaks. As you know it's a lot of work to get to them. So I will ask you, what would you think this would be? Does it sound like I am on the right track?
I would say yes. I would think your 2nd black wire is grounded some were. Wire nuts can deal with a bit of voltage/heat so that seems a bit fishy.
12v wants the path of least resistance back to the battery. A bare spot in the wire or a pinch by a screw would dump the juice back the ground and heat up that wire nut. Chase the black wire down looking at any bend, kink, or possible rub spot.
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Jim&Peg
Central Ohio
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Since you had voltage with the wire going to the brakes unhooked, but it dropped to 0 without blowing a fuse when re-hooked would indicate a weak connection in the wiring ahead of the point you were measuring. A weak connection can carry the trickle needed for the voltmeter, but not enough to run anything. I would start working forward with the meter connecting and unconnecting wires until you find the weak point.
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chassis
Penn's Woods
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Joined: 07/30/2003
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Agree with all of the above. Here are the things to check:
- Verify 12V at wires for each trailer wheel. If no 12V at wheel, trace wiring for chafing, and proper connection at junction box. If no 12V at junction box, verify proper operation at tow vehicle 7-way plug. If no 12V at 7-way plug, diagnose brake controller or blown fuse on tow vehicle.
- Verify proper magnet operation at each trailer wheel, when tow vehicle break pedal is depressed. If 12V and no magnet operation, replace the magnet.
- Verify proper braking operation at each trailer wheel, same as above. If good 12V and magnet operation at each wheel, but no braking action, check/replace brake linings and/or linkages.
- Verify 12V across breakaway switch. If good 12V at switch, pull lanyard and verify 12V at each wheel. If no 12V at wheels when lanyard is pulled, replace breakaway switch.
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