12V electrical problem

[GDBurk]

2010 30.5 rls 5th wheel is experienceing an electrical issue. Plugged in to the truck I have 12 V power unplugged, nothing. I have a solar system as well but I'm trying to fix a water pump problem and cannot do that without 12v power. I've had it at a dealer's and they're having some difficulty finding the problem. Ideas?

[JimD]

I will assume that the charging line from the truck will feed directly to the battery. Since you have 12 volts when connected to the truck that means the positive power feed from the battery to the fuse panel is good. Not sure how the ground connection is made. It may have a cable feed the battery or it may just connect to ground as soon as it enters your rig.

You will need a simple voltmeter to be able to troubleshoot the loss of your 12 volts. Hard to believe the dealer can't find the problem as loss of power should be very easy to find.

Anyway, here are some things to check:

1. Is there a battery disconnect switch that accidentally got pushed?

2. Is the battery any good. Check across the battery when the truck is not connected.

3. Is the ground cable connection good at the battery? The ground cable will go from the battery negative terminal to chassis ground. The connection to the frame needs to be clean and tight.

Your solar will most likely be connected to the battery to charge it. If the battery is good it appears you have lost the connection between the battery and the fuse panel. Since the truck voltage makes it OK the most obvious way to lose the 12 volts would be the battery ground connection.

These are the thoughts off the top of my head. Good luck!

[mrmom]

It sounds to me like you don't have connection between your battery and the trailer. That is why you have 12v when plugged into truck. I would check the connection where the 12v lead from your truck connects to the 12v feed wire for the trailer. There should also be a third wire at this connection that goes directly to the battery positive terminal. These connections should be in a 4" square electrical box mounted on the trailer tongue.

Like stated above, check for a battery disconnect switch on the battery wire or possibly a blown fuse.

[MtnGoat]

Its disappointing that Jayco has diagrams of the item locations, but no schematics to help us troubleshoot simple problems like these.

[Firefighter16]

I just copied this from a post I made earlier about getting a wiring diagram.
I've had quick responses from Jayco to my online or email inquiries. They sent me electrical and plumbing schematics and have helped with troubleshooting issues. I haven't tried calling them but that's worth a try to. For online, you can fill out one of these forms (need your VIN) and they'll get back to you quickly (in my experience): https://www.jayco.com/contact-us/
You can also email them at service@jayco.com (for towables) or motorizedservice@jayco.com (for motorhomes). Good luck!