Electrical Help

national757 · 12-31-2017, 12:27 AM

Lost all 12 volt power to inside the trailer. Runs fine on shore power, so the the converter is working, however when you unplug it, everything goes dark. There is no power present on the 12V battery lug on the converter when unplugged? The schematic shows a 20 amp fuse between the battery and the converter somewhere, cannot find it. Batteries are new, electric jack and the charging panel are working. You can run a jumper to any circuit behind the fridge and it works as well. I assume that the wire from the battery to the converter goes behind the fridge somewhere?? Got a trip next week....Yikes.

**commodor47** · 12-31-2017, 06:42 AM

It sounds like you may have a blown 30 amp fuse to the house battery. The inline 30 amp fuse should be just before the positive battery terminal. It may be a glass fuse which you might consider replacing with a blade type. Once you locate the fuse test it for continuity. A visual inspection may not indicate a short.

Dick

national757 · 12-31-2017, 10:36 AM

Hi Dick: Thanks for the reply. I did do a quick check of fuses on the battery, I don't have any round fuses, they are all blade type and appear to be ok. I did change out a small panel above the fridge, so I was in the space behind the fridge, but no wiring was touched. I'm wondering if the main battery wire is spliced in there? Never had any issues previously.

Rob

**Bill** · 12-31-2017, 11:35 AM

What is the year and model of your TM (this helps us identify which converter you have). Or even better, what is the make/model of the converter?

Quote:

There is no power present on the 12V battery lug on the converter when unplugged?

Is there power on the battery positive post?

Quote:

The schematic shows a 20 amp fuse ...

Which schematic?

Quote:

electric jack and the charging panel are working

With the trailer plugged in to shore power, or unplugged?

Quote:

I did do a quick check of fuses on the battery

Is there more than one fuse on the battery? If so, one is probably the fuse for the electric jack, the other is probably the main battery fuse that Dick is referring to - a fuse that is within 6 inches of the battery positive post. This is the fuse in Dick's first picture, although his is a cylindrical glass fuse.

The main battery wire should run directly to a lug on the converter. It is not "spliced in" anywhere.

There should be at least two wires on the negative post of the battery. (Since you have an electric jack, you most likely have three wires here.) As shown in Dick's first picture, one is white and runs up into the TM (to the converter). The other may be white, green, or bare as in Dick's first picture, and runs to a screw that is driven into a frame member. Are you sure that both are connected?

With a bit more info, this shouldn't be a tough issue.

Bill

BrucePerens · 12-31-2017, 11:37 AM

Fuses that look good can still be bad. Pull them out and test them with an ohmmeter. Then test for 12v on both sides of the battery fuse holder. If you have an aftermarket battery protector (which I recommend) check that it has not tripped.

national757 · 12-31-2017, 12:23 PM

So I have a 2007 3023. There are 3 blade fuses on the battery, all checked good with a meter. I took another look at the converter, and there is a 30A circuit labeled "tongue jack", which is not correct, and that fuse was blown. That circuit is the whole 12 volt interior, lights, pump, fan, everything. The tongue jack worked with that fuse blown, so I never checked it. The jack is apparently wired directly to the battery. My unit is stock, so I guess it was wired this way from the factory.

Thanks for all of your help, this forum is the greatest. Happy New Year!

Rob

**Bill** · 12-31-2017, 01:45 PM

I certainly learned something from this. To my knowledge, the tongue jack is always separately wired (or is that only for aftermarket installations?) That would seem to mean that the converter manufacturer reserved one fused thru-connection for an electric jack if installed, and TM chose to use that connection for all internal 12-volt wiring. Why? I have no idea. But I will remember it. BTW, 30-amps should have been plenty for that use, so we still don't know why it blew. Lots of possibilities.

Off hand, did you notice who manufactured the converter? In 2007, I would have guessed WFCO, but I'm not sure.

Bill

tentcamper · 12-31-2017, 05:18 PM

There should be some fuses 30 or 40 amps fuses in the converter box for the battery.

Craigrrr · 01-01-2018, 04:14 PM

Quote:

Originally Posted by national757

So I have a 2007 3023. There are 3 blade fuses on the battery, all checked good with a meter. I took another look at the converter, and there is a 30A circuit labeled "tongue jack", which is not correct, and that fuse was blown. That circuit is the whole 12 volt interior, lights, pump, fan, everything. The tongue jack worked with that fuse blown, so I never checked it. The jack is apparently wired directly to the battery. My unit is stock, so I guess it was wired this way from the factory.

Thanks for all of your help, this forum is the greatest. Happy New Year!

Rob

Yep, that is how our 2008 TM 2720 is also 30 fuse marked "tongue jack" as well.

national757 · 01-01-2018, 06:03 PM

I would try to pull that fuse and I bet all of your interior will go dead. Not sure why mine blew, but I put another one in and so far no problems. I think one of the fuses on my battery may be the tongue jack, and that appears to be wired directly, instead of running through the dedicated circuit. I have been slowly going through the wiring in back of the fridge, getting rid of twist connectors and cleaning everything up and trying to label all of the wires. They don't make it easy with the water line run through the middle, smashing the vent for the fridge, that will be a future project.