Brake Controller Showing Short in the System

[MegaJohn]

On the way home Sunday from our last outing our brake controller reads a short in the system. We made it home safely, but the brakes were in & out the whole way home.

I used my test light to check the brake wire to positive at the 7-pin connector and it would light. I'm not sure this is a good test though, as it may have only completed the circuit.

If I use my ohm meter, could I narrow my search to the truck or the camper? If it's in the camper, I expect I could then remove each drum's magnet from the circuit by cutting the wires leading to the drum to find which is having a problem.

I'd like to avoid having to pull each hub to check the wires inside... I just packed the bearings last spring. I could do it, just trying to avoid it if I can.

Now that I think about it... Could I disconnect the brake system's ground then test the brake wire to positive?

As you can see, I need assistance from others more experienced. Thanks in advance for your help!

Happy Camping!
John.

[RCMAN46]

MegaJohn wrote:
After much frustration and checking the wires in each hub (no issues found), we purchased another controller. About 450 miles later, we've had no problems with shorts.

Thank you to all who responded.

Happy Camping!
John.

What controller did you buy. I suspect you still have a brake issue and lets hope it does not come back and bite you in a bad way.

I am basing my response from one of yours last winter.

"I had a spare brake controller for the truck and changed it out. Our primary controller is a Hayes Genesis... the spare is a Draw-Tite, but I don't recall which one.
We hooked up the camper and the brakes seemed to work at first… then stopped working before we got on the road. "

[MegaJohn]

After much frustration and checking the wires in each hub (no issues found), we purchased another controller. About 450 miles later, we've had no problems with shorts.

Thank you to all who responded.

Happy Camping!
John.

[Sluggo54]

I have been down the road of chafed wires inside the axle. I have also had the socket on the truck partially disassemble itself, causing intermittent shorts and opens.

[LAdams]

MegaJohn wrote:
I don't mind so much pulling the hubs off... but would like to narrow my search to one or two instead of pulling each one to find the last had the short.

Yeah, unfortunately there is no easy way to do this - if the new controller doesn't solve the problem, then you'll have to pull the hubs one at a time... A bit tedious I know but it may become necessary... Hope you find the problem without too much difficulty and aggravation...

Les

[Steamguy]

just me wrote:
... install a resettable breaker, get rid of the FUSE in the brake system...

Do NOT EVER put a fuse or breaker between the controller and the brakes! If the fuse or the breaker opens under load, then YOU HAVE NO BRAKES! How do I know this and why am I shouting? It happened to me! The bonehead who wired my system up (a couple trucks ago) put in a thermal breaker between the controller and the brakes, and he put it under the hood. So it's a hot day, I'm in the mountains on a curvy road, and suddenly I have no trailer brakes...! Talk about having your hair stand on end! Once I finally got pulled over and my heart rate returned to normal, I found and fixed the problem.

The brake controller itself is fed from a fused line, and your controller is made to handle a dead short with no problem. Most of the really cool, modern ones (like yours) can indicate a fault. The thing is, most of these faults are intermittent, and your controller will continue to send regulated current down the line in spite of the fault.

But please, for your safety, don't put a fuse, fusible link, or breaker between the controller and the brakes.

[facory]

If you haven't found the 'smoking gun', like you said, the short is still there just waiting to touch bare metal again. It may decide to do that just when you need your brakes the most. If it were me, I would have a qualified technician hunt down and fix the problem. Brake failure is a HUGE risk to all involved.

[MegaJohn]

just me wrote:
When mine indicated a short I decided to stretch the wire in the axle by pulling on it, this will reposition the wire and the short went away temporally. So a new wire was installed out side the axle housing, no more problems. Also install a resettable breaker, get rid of the FUSE in the brake system and the charge systems.

Yeah, since I never found a "smoking gun"... I am concerned that there might still be a short someplace that I've not found and only moved the bare wire so that it is not shorting right now.

If the short comes back, my next step will be to rewire the brakes from the 7-pin wire harness to each drum.

Installing a fuse in-line is a simple change... I may look into that. If a separate run is installed for each drum, a fuse in each run would indicate where any future short can be found. What amperage rating would you recommend?

Happy Camping!
John.

[facory]

Encountered the same problem. We found a broken wire inside one of the wheels. Put is back together and never another problem.

[just_me]

When mine indicated a short I decided to stretch the wire in the axle by pulling on it, this will reposition the wire and the short went away temporally. So a new wire was installed out side the axle housing, no more problems. Also install a resettable breaker, get rid of the FUSE in the brake system and the charge systems.

[MegaJohn]

spike99 wrote:
Many trailers use thin 12 guage wires (especially inside the hallow axle tubes) and their factory brake wiring is linear configuration as well. For each of my trailers, I simply remove the factory junk wiring and replace with thicker 10 guage double insulated duplex wiring. And, install in a STAR design configuration outside the axles.

If you want better than factory brake wiring under your trailers, upgrading to much better STAR configuration is worth it. Glad I do this upgrade to all my RV, Utility and boat trailers.

Yeah, if our problem comes back, I expect our next step will be to replace the wiring. If it comes to that, it may be best to run a seperate pair of wires to each drum.

Hopefully our problems are solved for now. 😉

Happy Camping!
John.

[spike99]

Many trailers use thin 12 guage wires (especially inside the hallow axle tubes) and their factory brake wiring is linear configuration as well. For each of my trailers, I simply remove the factory junk wiring and replace with thicker 10 guage double insulated duplex wiring. And, install in a STAR design configuration outside the axles. For before and after, see below pictures.

If you want better than factory brake wiring under your trailers, upgrading to much better STAR configuration is worth it. Glad I do this upgrade to all my RV, Utility and boat trailers.





.

[westend]

Before you pull the hubs, I would check the wires to the connector on the truck. It's easy enough to inspect. I was pulling at my hair and finally found that the brake wire to the 7 pin connector on the truck is at the bottom. The wire to my connector must have been hit by a road hazard and the semi-parted wire was corroded and only giving intermittent power to the connector. I had to strip the sheath off the wire to find this but could feel the break, first, by moving that wire.
Good luck with the brakes.

Whoops, saw you have it fixed, travel on!

[MegaJohn]

After scratching my head for a bit... I think I've found my "short circuit" problem. A new brake controller seems to have fixed my issue.

I've also now inspected every inch of the electric brakes... in all four drums. No actual short was found, but all brakes are inspected and bearings are all greased and ready for next season to begin!

We put over 300 miles on the camper yesterday with the new controller and had no problems.

Our next project... new ball joints for the Dodge. 😞

Happy Camping!
John.

[MegaJohn]

LAdams wrote:
I think John that you will find that you have an intermittent short being caused by a brake wire inside a wheel hub that has broken loose form it's metal clamp and the wire has rubbed thru the insulation on the inner hub of a wheel...

I had 2 shorts like this with 2 different trailers and in both cases, it was exactly that... I know you don't want to pull the hubs but I would be willing to bet that is where the problem lies...

Pulling the hubs isn't that bad and you don't have repack the bearings again if your careful with the removal and re-installation of the hubs...

I know you don't want to hear that, but my money is on a brake wire short inside a hub 😞 :R

I suspect that your brake controller has now stopped working because the controller now is "fried" because of the short... I also experienced that on the first failure as previously mentioned...

Les

Thanks Les. I suspect you're right, but I hope I've not damaged one (or both) of my controllers in the process.

I don't mind so much pulling the hubs off... but would like to narrow my search to one or two instead of pulling each one to find the last had the short.

If I have to, this weekend I'll pull each hub for inspection... the weatherman is calling for mostly sunny skies with temps in the mid to upper 60's. Sounds like a good weekend to work on the camper. 😉

Happy Camping!
John.