Trailer lights work but getting error and no brakes

jddodge · Nov 30, 2008

Hello

I have 2001 GMC Yukon with Reliance electronic brake controller. Controller was professionally installed and worked great for the past year stopping my 18' call hauler. Last month I started getting E1 error, I still have running and brake lights but no brakes. E1 = no connection (from what I can dig up). I have visually checked the plug (male and female) both look OK. Suggestions?? Thanks Jonathan

kenmac · Nov 30, 2008

Do you know if they installed a circuit breaker in line with the trailer brake wire ? Some people do. I did on mine

Diamondpilot · Nov 30, 2008

Start checking the wiring on the trailer and check to make sure you have voltage on the trucks trailer plug when a helper applies the brakes. My guess is its a trailer problem though.

Chris

J_J · Dec 1, 2008

I am assuming that you have a 7 pin plug and receiver. and even if you have a 4 pin plug, they make a coupler test plug with LEDs to help you troubleshoot your wiring. You can use a multimeter to test out the trailer wiring. They also make a voltage tracer to find open wires. I purchased mine from Home Depot, and it has a transmitter and receiver. It worked very well.

KeithInSpace · Dec 1, 2008

I'd check fuses in the truck's main fusebox first. On mine, there is one that gives power to the brakes on the trailer. After that, I'd check for an in-line fuse somewhere as others have suggested.

Sometimes one of the spade connectors in the cable can get 'flattened' and not make proper contact (the female one, I mean. On the trailer side). I'd probably also poke around with a small screwdriver and pull the contacts off the wall to make sure they are all doing what they should.

Worst case is a rubbed and grounded wire. Nothing a couple of ours with a multimeter won't fix.

I'm sure there is a fairly simple solution...just need to find it!!!

MarkLeininger · Dec 2, 2008

No connection means it doesn't think the trailer is supplying a resistive brake circuit for the controller to power. So:
On the trailer connector, connect your ohm meter to the brake hot wire and ground wire. It should measure a very low resistance, probably on the order of a few ohms, depending on how many brakes you have and how much corrosion you have on wiring connections. If it measures 0 ohms, something is shorted to ground, possibly one of the magnets since they get really hot. If it measures infinite resistance, either a wire is broken or one of the magnets has failed open. Try to find where the brakes are grounded directly to the frame and take your measurement there to see if there's any difference. If there is, there's a problem between the trailer ground and the connector pin.

The other thing you can do is take a car battery and connect it to the trailer brake hot and ground wires. You should hear the brakes actuate. If none of them work, it's almost certain theres a problem with a wire (or ground connection), or else all 4 magnets have failed, which is unlikely. At that point I'd start disconnecting magnets one at a time and applying the battery to them to see if one is a problem. If all work, it's a section of the wire from the magnet to the connector.

If you end up doing any rewiring, tear it all out and do it right or you'll be going through this every time you go on a trip.

jimainiac · Dec 6, 2008

MarkLeininger said:
No connection means it doesn't think the trailer is supplying a resistive brake circuit for the controller to power. So:
On the trailer connector, connect your ohm meter to the brake hot wire and ground wire. It should measure a very low resistance, probably on the order of a few ohms, depending on how many brakes you have and how much corrosion you have on wiring connections. If it measures 0 ohms, something is shorted to ground, possibly one of the magnets since they get really hot. If it measures infinite resistance, either a wire is broken or one of the magnets has failed open. Try to find where the brakes are grounded directly to the frame and take your measurement there to see if there's any difference. If there is, there's a problem between the trailer ground and the connector pin.

The other thing you can do is take a car battery and connect it to the trailer brake hot and ground wires. You should hear the brakes actuate. If none of them work, it's almost certain theres a problem with a wire (or ground connection), or else all 4 magnets have failed, which is unlikely. At that point I'd start disconnecting magnets one at a time and applying the battery to them to see if one is a problem. If all work, it's a section of the wire from the magnet to the connector.

If you end up doing any rewiring, tear it all out and do it right or you'll be going through this every time you go on a trip.

Just want to mention that if you use a battery to test the circuits of the trailer, wire in a fuse or circuit breaker for safety.

Soundguy · Dec 7, 2008

Ditto what has been said.. I have a hoppy controler that uses he same E1 code.. and it mens the power wire out to the brakes does not see a path to ground.. check and wire nuts or tap splices from the brake hubs tot he wire harness. i jst redid my dexter-brake axles and trailers with new wires and connectors and all. too much corrosion ad gotten in them.. etc.

soundguy