Brakes -short circuit/grounding issue


I posted last year about a problem with my brakes. I thought I had the problem solved but apparently not. Sporadically my controller shows the "S.C" readout and my brakes aren't working. I try different things, ie: plug/unplug the main cable...sand the contacts...wiggle the wires right at the brakes..and it will work for a bit, and then same thing, the "S.C" comes on and no brakes. This all happens while driving; sometimes they work, sometimes they don't.

So I youtubed how to fix brakes and it shows how important the ground is. But nowhere can I see my brake wiring grounded. They're all connected to a 2-wire cable that goes straight to the main wiring junction box and then a separate positive and negative cable to the batteries. Are there some trailers that DON'T use the frame as the "ground"? I can't seem to find anywhere where the negative is "grounded" to the frame.

But I don't know if its a grounding issue or if there is a "short" somewhere. I know the "S.C" reading means "short circuit". I've tried to follow the wiring right from wheel to junction box and other than where it goes through the axel, I can't find any worn wiring jacket.

The 7-plug connector that goes into my vehicles plug-in is quite corroded on each contact. I've taken some emery clotch and sanded them, tightened them up and re-plugged, and it will fix it for a bit, but again not permanently.

Any RV mechanics on here that can give me some suggestions? I'm tempted to replace absolutely everything right from the wheel brake all the way to a new 7-pin plug. But I'm thinking it's probably just one tiny little spot that's causing the problem.

Help!
 

akjimny

Senior Member
Re: Brakes..short circuit/grounding issue...

Dave - Based on what you said about cleaning up the 7-plug and the problem going away for a while, I'm guessing that's where the trouble is. My trailer plug on the motorhome was also really corroded and I ended up replacing the whole plug. Only took a couple of hours and no problems since. You might try that. Good luck. :) :)
 
Re: Brakes..short circuit/grounding issue...

akjimny - 8/21/2011 12:35 AM

Dave - Based on what you said about cleaning up the 7-plug and the problem going away for a while, I'm guessing that's where the trouble is. My trailer plug on the motorhome was also really corroded and I ended up replacing the whole plug. Only took a couple of hours and no problems since. You might try that. Good luck. :) :)

Good to know. I'll try that first. Quick and easy job. Usually its the simplest things that cause the problem. Here is what mine looks like:
 

akjimny

Senior Member
Re: Brakes..short circuit/grounding issue...

That doesn't look as bad as mine was. I had corrosion not only in the connector but also in the wiring. Luckily the manufacturer left enough slack so I could cut the corroded wires back to good metal.

Like you said, it is a cheap and easy fix. Under 2 hours and less than $20. :) :)
 

Pancanbob

Senior Member
RE: Brakes..short circuit/grounding issue...

Hi, Dave
Saw your Picture of the connector, it doesn’t look that bad, you may want to try this “Deoxit” “ http://store.caig.com/s.nl/sc.2/category.188/.f “
It’s a Contact cleaner and rejuvenator then use a dialectal grease to help keep the connection clean

Permatex makes good dialectal grease for electrical connections.
(URLs below)

http://www.permatex.com/products/au...e/auto_Permatex_Dielectric_Tune-Up_Grease.htm

If you do replace the connector, still use a “dialectal grease” to keep the new connector from getting Corroded.
Do they use salt on the roads in Alberta? If so this would help.
Take care, hope this helps.
Pancanbob
 

H2H1

Senior Member
Re: Brakes..short circuit/grounding issue...

Well you guys got me to thinking, so I went and took a look at mine. Well it is dirty/corrosive some what. I did notice last time out the lights on the toad did not work, so maybe this why. Pancanbob I am going to the auto part store and get the permatex and do some cleaning. Thanks guys
 

Pancanbob

Senior Member
Re: Brakes..short circuit/grounding issue...

Hi, Hollis
When I was living in Panama, I would have to clean my battery post every 3 or 4 months.
After I started using the “Dialectal Grease” it was 2 or 3 years.
The stuff works by keeping the water out, and stopping corroding.
Take care
Pancanbob
 
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