Troubleshooting Da Electric Brakes

Nomad

With the weight of my Jeep I've never really had to have the brakes turned up much except for the really steep grades so when they quit working back when my hot wire and brake wire burnt through and got that fixed, I zoned and didn't check the brakes untill two weeks and several hundred miles later. Haven't really needed them but will so am trying to troubleshoot. The situation...
1) Have traced and checked the wiring from the battery to the TV seven pin. All looks correct and there's power to the brake controller (blue wire). If I understand how this works, the brake controller puts out a variable amount of current to the seven pin (and T@B brakes depending on how hard you press the brakes (proportional) - when I volt meter the seven pin I get a 12v+ reading no matter what (TV off, TV running, brake depressed or not) - doesn't seem right from what I've read.
2) Based on #1 - if I'm correct on that - With that current going to the T@B, the brakes should be locked up, they have never been. One should be able to have sensed that and there's no flat spots on my tires.

Haven't traced current through the T@B brake wiring but it all looks intact.
From talking to people and reading, the safety brake, when the cable is pulled, sends a current to the brakes and activates them - this is usually supplied by a battery - Don't see a seperate battery so presume it's getting it from the TV or T@B.

Any insight would be greatly appreciated.

Nomad

Another tidbit - the little LED on the controller would light up indicating you were connected and good to go. Doesn't.

Nomad

One theory is there's an inline fuse somewhere that's blown - Haven't found one though.

Ron

Brake controllers have two fused wires to them.  One supplies power to the controller, it lights up, and comes from a factory supplied connector which will be fused or a circut breaker in the vehicle's fuse box or an after market wire run to the battery and fused with preferably a circut breaker at the battery.  The second required fuse could be part of the brake light switch.  On my Jeep Wrangler this is actually a fuse in the fuse box for the third brake light.  If controller lights up but the brake pedal does not activate trailer brakes this is a good place to look.  Trailer brakes will still work with the slide switch, just not with the brake pedal.  One wire to 7 pin connector is always hot to supply power to trailer battery for brake-away brakes.  On the Tab this is also the trailer house battery.

Nomad

Ron...Thanks for the response...
There is a small, self resetting circuit breaker on the line by the battery - hot on both sides.
The only wire connecting to the Jeep brakes is tapped to a brown wire (no fuse inline) - will have to get into the Jeep fuse box - haven't yet.
The indicator light on the controller does not come on.
Brakes don't work with the slider.
Have traced the hot wire for the battery charge back to seven pin, it's hot, ok.

The brake controller contact in the seven pin is also hot - that seems weird to me. I would think it would only become hot when the brakes are pressed. Being hot, I would think it would lock up the trailer brakes, it doesn't. Could it be hot so when plugged in the controller senses the brakes/hookup and then the brake controller takes over? It used to be that the controller light didn't come on until hooked up.

Nomad

Just looked at the fuse diagram in my Jeep manual, found the third brake light fuse and it was good, no blow there.

Nomad

Ok, am hittin the road in the morning so unless someone has a suggestion/solution today/tonight I'll have to hit an RV or trailer place before heading west into unknown hills.
Anyone?

Ratkity

PXL, are you using a 6pin to 7pin adaptor? There are 2 industry standards. One is for industrial use heavy-duty trailers and a friend of mine locked the brake on her horse trailer and thought the wiring on either trailer or truck was borked. Figured out her Dodge wiring was fine, the trailer was fine - discovered the adaptor was the wrong one (6pin to 7pin).

Yes, the breakaway cable gets its power from the battery. Found that out with the popup by accident. 

Nomad

Ratkity - No adapter, std. 7-pin - As mentioned, used to work.

Ratkity

Sorry PXL, it was the only thing I could think of. The blue wire should be hot when the brakes when you press them on, just like you said. The black wire is for charging the battery. Sometimes, some vehicle manufacturers make #7 (center pin) hot. The center pin really isn't there for anything for standard towing. There may be a use for it in commercial vehicles or bigger campers/RV, like running lights to a dingy? Just guessing. If everything was working prior to this and you get current to your blue wire when you press the brakes in the Jeep, but not in the rear connector, there's a loose connection somewhere or you have a ground/neutral wire touching the blue wire. Also sounds like the black and center wire might be crossed if the center is suddenly hot, but wasn't prior to this.

I wish you luck. You said you were going to stop at a mechanic's place today. Let us know what happened!

PS I know Ford Explorer Sports have 2 hot wires to their tow package - different colors and the tech hooked up Sis' controller wrong and it blew up (started smoking!). I know there's a few unique towing packages in certain vehicles with wires that are colored differently. The fact yours started out working fine doesn't follow a "wrong" initial connection, but it could explain a loose one.

jctangney

Just a comment on your "when I volt meter the seven pin I get a 12v+ reading no matter what (TV off, TV running, brake depressed or not) - doesn't seem right from what I've read" statement. When I had the hitch receiver and brake controller added to my TV, I also tested it and saw the 12+ reading all the time for the brakes.  I checked with the place that installed it and he told me the brake controllers always send a slight current to the brakes so they can detect when it is actually connected to a trailer. So, seeing the 12+ reading when you are not depressing the brake pedal is normal based on what he told me.

John

Nomad

John - Thanks - That's what I figured, it has to electrify the magnets I suppose to sense the hookup.

Ratkity - Did some more troubleshooting before I broke camp - fellow camper suggested we hookup to a couple other trucks and see if it lights up their controllers - nope. So that means it's on the T@B side. In talking with another camper he surmised that my original shorts, along with blowing both the T@B and Jeep battery fuses probably blew out the magnets in the breaks (or something in there). So, headed north to my favorite RV repair place in Kingman (Trotters) and they basically said "no big deal, we've got the parts in stock". So, I'll be ready to roll it into there shop when they open tomorrow morning.

Nomad

A boondocking (BLM) night outside Kingman, AZ - A close run in to the fixit shop...

Ratkity

Magnets and sensors? I learn something new everyday.

Nomad

Yep - Know nothing about such things.
Well, I'm off to see the wizards, hopefully will have brakes by noon.

Nomad

Well, scratch what used to be my favorite repair place (Trotter/Kingman) off my list. Has always been first come, first served. Was first there but somehow third in line, no guarantee they could get it done by end of day and wanted a $45 priority fee to even have that possibility.

Nomad

Ok, this is getting rediculous...
Stopped at a brake place, asked the old guy what he knew about electric trailer brakes. He responded "more than I ever wanted to know". So we discussed my situation and the electric brake plate/assembly is $300+ per wheel (both may not be bad, only takes one to shut the system down). Then I mentioned that I had 12.5v on the TV seven pin brake lead no matter, truck on, truck off, on and brake applied - Says that's not right, should be nothing until truck on and brake applied. Recommends getting it rewired and a new brake controller before I do anything with the brakes as they're so expensive.
So, conflicting opinions - others have said there should be power there - I should have checked on Verna's while she was in camp - Could someone check theirs? - Would appreciate it.
Of course then there's also the fact that when I plugged into another campers truck, their brake controller didn't light up either so that pointed to the problem being on the T@B. But who knows, his wiring may have been hosed or his controller bad. He doesn't actively tow with it so couldn't remember when he had checked his.
So, no further ahead - The problem could be with either or both :-(

Any ideas/thoughts/opinions peoples?

Nomad

ST_Bob - Do you know detailed everything about everything? You amaze me!
So, here's a question for you - I'm not going to solve this myself - where should I take it to get this figured out?
If I wasn't full time on the road and had the tools I might play around - or if I was back in small town MN I know exactly who to take it to - I can't and I'm not.
And Massachusetts is too far to visit at the moment :-)

Nomad

I worked with engineers (medical, technical, computers) my whole career - One of the most knowledgeable guys I ever met (way back in 1969) was a tech writer - You remind me of him.

Verna

PXLated, on your "Check your bottom" thread, your picture is showing electrical wires. Are any of these wires damaged from the rock or whatever that damaged the box lid?  This is a electrical junction box so testing can be performed at a middle point between the 7-pin connector and the wiring coming from it. 

I have surge brakes on my T@B, which is why I had very little knowledge to impart to you concerning your electric brakes.  

Nomad

Verna - No. Checked all wires in there, all good. No sign of water, just dust/dirt. Traced brake wires out of there to brakes and all looked fine.

jkjenn

Is it possible there is a sensor that is so dust covered that it is causing mayhem?

Nomad

Jenn - If so it's inside the brake drum and I don't have the tools to check.
If I was back home I'd have this solved within a half hour. I'd find the local small town mech and it'd be done. Am thinking I might just wait till I hit a small town and hit up the mayor with the "who is the guy I need to talk to" question.

Nomad

Thanks Bob...
Since I barely know how to turn on my volt meter, I'm going to have to read, re-read, and re-read these instructions. It all makes sense, I just need to absorb ... Or find that auto electronics tech that already knows how to run his volt meter.
Even though I'm not adept at this, I know there are some here on the forum who could immediately pull this off so good info.

Nomad

Bob - There is a self resetting circuit breaker on the blue break line - it's up close to the battery. the short out was several feet beyond the brake controller itself. Don't know if the brake wire burnt all the way thru. They were next to each other but not necessarily touching as I recall. When the charge wire (black) shorted, it blew both the TV and T@B battery fuses. So how much juice got back to the actual brakes is hard to tell.

Nomad

Here's something though - Bob refers to low ohm setting and resistance, etc. which mean nothing since I'm not a multimeter guru but - When I checked the seven pin with a circuit tester (Verna and I checked with multimeter, std. settings), the led light came on. Current. BUT, if you use a circuit tester with an incadesent bulb, nothing, doesn't light up unless you press the brakes. And if you connect to the blue wire right by the brake controller and play with the controls you can dim and brighten that bulb where the LED version is just off or on.
So, with the new circuit tester I traced all the wiring back to the seven pin and it and the controller are ok. Tomorrow or the next I'll try to retrace the T@B wiring.

Yes, I know, all you engineering types and multimeter masters are probably amused at my follies. I got one thing to say to you as you roll on the floor...Oh I better not or I'll be in Verna's dog house :-)

Verna

PXLated, we don't laugh at those who struggle!  If you were down here closer, I'd be helping you. Using the volt meter is a learned process. The knowledge does not come over night, but must be learned, sometimes the hard way!

Nomad

Ok, guess the guy at the brake shop was full of it. Been researching and watching vids and turns out whole new electric brake assemblies aren't that expensive (1/10th the price I was quoted) and in fact you don't necessarily need the whole assembly, maybe just the magnet. Here's a vid - looks like if I was sitting in my brothers driveway I could manage it myself. Still need to trace the wires - or maybe not since they all look ok. It's looking more and more like it could just be blown magnets and anybody can replace them.
That's what I get for trying to save bandwidth and not hitting YouTube :-(
http://www.etrailer.com/tv-demo_trailer_hub_magnet_replacement.aspx

Nomad

And I understand you can walk into Napa (or any auto parts store) and get the parts. All the construction and lawn crew guys need them for their big trailers.

Ratkity

Wow about the magnets! Good luck!!! What is the estimate time for installing them? I suspect they float in some way in a track.

RZRBUG

What a hoot, not to mention very concise and informative.  Although I have surge brakes, I just finished installing new bearings, races, etc. (as you say, couldn't hurt), so I could relate to much of this procedure.

I used a large garbage bag to place everything on to keep it clean.  When finished you can throw dirty rags and any leftover parts on the bag, roll it into a ball and toss it.

Thanks for time and effort in putting this together.