Steve.
With your comment about the battery conn for the break-away pin, I decided to clean all the connections to the batteries--there was some corrosion evident. Used bicarb water to neutralize the gunk on the connectors, removed all leads and wire brushed after using the bicarb water--got everything clean as I could. Hooked it all back up and could not get a reasonable reading on the blue lead-to-ground--was all over the place.
(Remember, first measurement was 12.75 at batts, and 12.05 at blue-to-ground----or close to these numbers)
Made a decision to revamp all the connections to the batteries--been considering this over past 2 years, but never got around to it. Shopped around and came up with a distribution box used by stereo shops with 2ga in for both pos and neg, and 1 2 ga in/out + 3 smaller terminals for both pos and neg. Took the batteries out, cleaned everything, filled the batts with distilled water (some were low, but not below the plates) and connected everything back going thru the distribution box. I have really come up with a neater (but way expensive) wiring setup. Got everything back in and all systems are go on the trailer itself. Converter works and batteries show 13.55 volts with the converter running. BUT, no different reading on the blue lead to ground. VOM is bouncing all over.
I am sorry for changing horses in midstream, but I think I have any concern about the charging/battery system cleaned up. All connections are clean and tight. While I am not an electrician, I feel I improved the original setup many times over. All pos/neg feeds go to/thru the distribution box and everything in the trailer seems to be working ok.
But. the test you have set me up with doesn't work, as the voltage reading doesn't pan out.

Ideas? Suggestions?
And another large thank-you for your input.

Also, of course---WAY TO GO LONGHORNS! OU was way to ready to run over them.

Joe

 

Joe,

When you say the test doesn't work, what do you mean?

Steve

 

which batteries did you fill?

The power and electrical system in the trailer is separate from the road lights & brakes.

 

He's trying to establish a rough estimate of amp draw by using the breakaway circuit off the house battery. At least that was my goal.

 

Steve,
When I said the test did not work, I was using the wrong wire--finally got all the new wiring in and the batteries reinstalled. Had the converter on for a while--voltage is at 13.02 at the brake lead, 13.30 across the batteries. Just finished with the 10a fuse--weak spark when contact made, fuse did not blow.
Next step?
If I can help with your trying to figure this out, will be very willing to get a better meter.
Joe

 

I have to move the trailer out of the drive tomorrow--having a cover/storage shed erected. I hooked up and pulled forward slowly and applied the manual at 10.0 setting. You can feel drag but I can easily pull the trailer forward.
Joe

 

Joe,

If the fuse did not blow, it means the amp draw from the magnets on your brakes was less than 10 amps meaning not all the brakes are working. Now you can use your meter, one probe to the lead off the break-away and the other to the blue lead feeding the brakes to get an amp draw. You have one or more wheels that are not in the game when it comes to stopping. I am still betting on a chafed lead somewhere in the system.

You initially said there was one wheel that was silent when the brakes were activated, you might start there.

As to meters, as far as I am concerned anyone who is serious about troubleshooting their RV needs a high-end clamp meter that is capable of reading both DC and AC amperage. The ability to read DC is what you pay for. Lots of meters will read AC amps. I use a Fluke, but there are other good meters. I also like one that can backlight the screen as sometimes it is too dark to read in compartments and so forth.

Steve

 

couldn't the operation be checked with a different voltage source to stay within the capabilities of the meter?

I'd have to look into it a bit, but I'm thinking the power requirement would be fixed, which means a 24v source would half the amperage. I could be completely backwards and the impedance is constant which would mean a 6v source would half the amperage.

 

TXReb,
You are getting out of the realm of my abilities. I am of the school that needs a light to come on when something is working and not be on if a dud.
RVTech is trying hard to run a diagnostic from 1500 miles away, and I keep throwing curves at him.
I believe we have it figured to be in the trailer brake system, not the truck--which is like light years ahead of where I was for the last 3 years.
Now the question--if one brake is not working (and it seems to be the RF) how to get it down to wiring or magnet.
My trailer has NevRLube bearings--I have a 1 7/16" socket coming so I can remove the hubs and inspect the brake assembly.
I am willing to order new brake assemblies, but am afraid the RV Tech will disown me if I don't make sure what the actual problem is.
If he was local here in TX, the trailer would already be in his shop.

By the way, Reb, aren't you in the wrong Aggie camp?

Thanks,
Joe

 

Joe I think you are getting there. No buzz at a brake then trouble shoot the brake.

First check all exposed wiring..easy first, harder secondly.

Then pull the wheel and drum off and check the wiring and assembly.

 

Joe,

I agree with Scott. Do a lot of looking before doing any taking apart. It would be a whole lot easier if you was doing your learning on a simpler problem.

My only goal to start with was to verify what you reported hearing, that is one wheel was silent when the brakes were actuated. By putting a 10 amp fuse in series between the break-away lead and the blue brake lead, if all the brakes were working, the amp draw should have been more than 10 amps and blown the fuse, which did not happen. You know you have at least a partial circuit because you got a spark when you connected the fuse.

An earlier poster also suggested the trailer was the problem based on earlier voltage and amp readings, but I was not sure how they were taken. If you use smaller amp fuses until one blows, you will get an estimate of the actual draw. Crude, but should work.

There were several other indicators the problem is with the trailer or the trailer connection, but there have been so many prior attempts to solve this problem, I think it best to go step-by-step. Given it all together, my working hypothesis is the problem, once found, will be a simple one. We targeted the trailer brakes so far and we bypassed the seven pin cord and it looks like we have narrowed our search.

You are handicapped by lack of experience with trailer brakes and, like so many folks, a lack of the proper test equipment. Your strength is your willingness to muddle through this.

Certainly feel free to buy any parts you choose. I am just not sure yet, you know what to buy and the wiring that runs inside to the magnets is normally secured very well and is not the highest profile suspect.

As I recall a couple of folks in FTE had a similar problems and eventually rewired or found broken wires without ever opening the brakes.

Steve

 

Where the wires route under the trailer and are near the suspension is where I had one break once. It was rubbing.

 

A visual inspection/tug on wiring shows no wear/bare spots. But most of the wiring is routed thru the axles, or won't come out of the backing plate. Grommets are in place in the backing plates and the connectors appear to be the original ones that are about the size of a nickel with both wires routed into them on the same side.
Got a couple other projects on my mind today--was supposed to have a cover put up for the trailer, but raining--the rain also trumps my rolling around under the trailer to go over the wiring again.
I will get this fixe with all this help.
Joe

 

Joe, need to check for continuity of the wiring thru those axles.

 

Have you checked the wear on the magnets since the problem started?

I'd disconnect the one you say isn't buzzing and try it by itself. You can trade the 10A fuse out for a 2.5 if you're only checking one magnet. If it shows to be faulty, but you can't find a broken wire, I'm thinking the magnet has worn down to exposed coil.

If this is the case, it's likely that this was just the first to go.


Nope, not the wrong Aggie camp, just a different one. Some folks suggested I don't get three degrees from the same university. ;-)