House 12v Electrical Issue - 2004 Vectra

[emiddleb]

Looking for some thoughts on what to check next.. 2004 Vectra 40KD.

Problem - only about 1/2 of my OnePlace monitors are working, along with a couple other things related to the panel switches.

Working - the Dimensions inverter panel works, as does the holding tanks display. The battery display works for the engine batteries. Finally, the gen switch/display works.

Dead - Powerline EMS display, the water pump and both the gas and electric water heater switch lights. The water pump and water heater gas side does not work, not sure on the electric side. Finally, the House battery side of the battery display does not work.

Cause - I found one of the 12v 15amp resettable fuses on my bedroom panel had popped out... marked "Monitor/TV." Reset the fuse, everything working!

About 15 seconds later, the same fuse popped again. Tried with and without shore power, no difference. Fuse still pops after 15 secs (approx.)

Figuring start with simple fix, I ordered a new 15amp fuse. Installed, same problem. Works at first but after 15 seconds it pops.

Now I'm stuck where to go next. It's not the fuse since that was replaced. I'm thinking (and may be wrong) that since the fuse doesn't pop instantly but takes 15 secs that it's probably not a true short in the wiring but something is drawing too much voltage. Correct?

For grins, I tried turning off several of the 120v breakers (water heater, A/C, etc but no impact... 12v breaker still pops. For what it's worth, everything else seems ok. The Dimensions panel indicates all is ok there. All 120v items appear to be fine. Other 12v items (lights etc) seem ok. During the 15 seconds before the fuse pops the non-working items on the panel (Powerline EMS, pump, water heater switches) all appear to be working fine with no issues indicated.

If you made it this far, thanks for reading. Wanted to give all the data I could. Any thoughts on further diagnostics, things to check, etc?

[cbeierl]

Looking at the Body, 12 Volt Wiring Installation diagram for your coach, page 5 of the pdf shows the 12V breaker panel and indicates that the Monitor/TV breaker protects the power line labelled JA. According to the Wiring Identification Guide that line is:

JA / 14 YEL OVERCURRENT PROTECTION (15A FUSE/BREAKER TYPICAL) WATER PUMP,MONITOR PANEL,ETC (REF JP)

which matches your description of the affected items. Looking at the Body, 12 Volt Wiring Diagram we can figure out everything that is powered by that circuit. Here is the list I find, in the order shown in the diagram:

• Exterior Monitor Panel
• Load Shedder Control Board (inside 110V panel)
• Monitor Panel
• Water Pump Switch
• Water Heater Switch
• Outside Entertainment Center (connector located behind outside radio)
  • Wallplate - TV
  • Exterior Entertainment Center Radio
• (Wire Assembly Roof - Behind Bedroom TV)
  • In-Motion Satellite Power Switch
  • Switching System (for Satellite, presumably?)
  • Digital Satellite Elevation Sensor
  • Satellite ASM

I would start by seeing if you can rule out any of these as the cause of the problem. For instance, if you can unplug the Wire Assembly Roof connector behind the Bedroom TV you should be able to see whether any of the Satellite wiring on the roof is the problem. If the breaker doesn't pop with that unplugged then you know you need to check out the Satellite wiring--if the breaker still pops then you know that's not the problem.

Next I might try to unplug the Outside Entertainment Center connector, located behind the outside radio. Finally, I would try to unplug the Outside Monitor Panel.

Hopefully one of those will isolate the problem area, but if not you would need to check out each of the other items in turn.

[FIRE UP]

Chris,
EXCELLENT research and advice Sir! This is quite and interesting problem the OP has. As you know, our coach is very, very similar to both yours and the OP's being it's an '04 Itasca Horizon 36GD with the CAT C-7 330HP. The switching, breakers and wiring is all very close. I'm gonna be following this thread to see just what the OP finds out that was/is the problem.
Scott

[emiddleb]

Semi-success!!

After a ton of work, I have determined that it's the Powerline EMS shedder circuit board in the 120v breaker box or the associated wiring. When I disconnected the 12v connection to the board (8 pin) the problem breaker did not pop. So the EMS function/display is disabled, but all other stuff on the JA line (water pump, tank monitors etc) are working fine.

Will still have to figure out if it's the board or associated wiring, but at least determined the core issue and have functionality back on the rest.

Thanks again to all for helping me find the problem.