No power to coach unless RV is running

[dvleemin]

OK,
I have a really weird electrical problem in my 2005 Itasca Horizon 40AD. I just put the batteries back in after winter, and now I am getting no 12V power to the coach unless the RV is running.

Here are the symptoms:
- no 12V power to coach unless the RV is running
- if the RV is running the battery disconnect switch works
- if the RV is running the battery disconnect switch does not work
- If I plug in the motorhome, the inverter starts humming but I get no power
- If I go in the motorhome and turn on the inverter, I do get 110V power
- the generator does not start (does not even turn over)

Here's what I've done so far:
- cleaned all the connections to the coach battery and confirmed that there is power to them
- I checked the 12V coach fuses under the bed
- I checked the 12V chassis switches outside by the drivers front
- I checked and there is 12V power going in to the inverter

I am running out of ideas. Does anyone have any thoughts?

Thanks,

Darryl

[trackman]

If everything was working when you took the batteries out you may have some connection problems when you installed them. Go over the wiring set up for the batteries again.

[Fl_Richard]

Hooked up the batteries incorrectly blowing the reverse polarity circuit breakers allowing only vehicle generated power to operate????

[dvleemin]

Originally Posted by trackman

If everything was working when you took the batteries out you may have some connection problems when you installed them. Go over the wiring set up for the batteries again.

That was my initial thought as well . . . but I can't find anything wrong. . .

[dvleemin]

Originally Posted by Fl_Richard

Hooked up the batteries incorrectly blowing the reverse polarity circuit breakers allowing only vehicle generated power to operate????

What's a reverse polarity circuit?

I did check the main fuse by the batteries and its fine:

[tkdavis]

Not that this will help solve your current problem...but just a tip for the future:

Now that smartphones have put a camera with us all the time, I don't take anything apart before I snap a picture of it. That way, when I am going back together with it later, I don't have to second guess if I am hooking it up right!

Good luck with your 12v issue!

Terry

[gfs1943]

Is your Aux Battery switch on the dash turned on?

Your post is a bit confusing in this area:

"- if the RV is running the battery disconnect switch works
- if the RV is running the battery disconnect switch does not work"

Which is it?

The humming from the inverter when you plug in is most likely the charger portion working, trying to charge the house batteries.

The big fuse shown in post #5 above is in the feed line to the inverter.

It really sounds like you are not getting any power from your house batteries; that's why the generator won't start. Try using the Aux Start switch and see if the generator will start.

If everything is wired up correctly, you need to run a capacity test on the house batteries.

When you get it figured out, please post your solution here. Thanks!

[dvleemin]

OK.

Took all the batteries out. Then scrubbed all the wires. Low and behold some !@#$ had painted (at least I think its paint) one of the red wires black. So it was simply a problem with it being connected incorrectly.

Thanks for everyone's help.

[gfs1943]

Thanks for posting the solution.

[gemini5362]

Originally Posted by dvleemin

OK.

Took all the batteries out. Then scrubbed all the wires. Low and behold some !@#$ had painted (at least I think its paint) one of the red wires black. So it was simply a problem with it being connected incorrectly.

Thanks for everyone's help.

A good lesson on why you should never just look at the color of the cables. There are a lot of diagrams explaining how to hook them up.