Paralleling Solenoid Wiring - Fire Hazard??

[dc_mystic]

Recently purchased a used 2018 Greyhawk 29MV, and drove it 1,100 miles home from the previous owner's house. All the way home, the coach/house battery was not being charged by the chassis alternator. I've spent the last week going through posts here on JOF, and exploring the electrical system trying to resolve the issue, and I think I have uncovered a serious problem and I am wondering if this is something unique to our unit, or if there was a error in manufacturing that could mean that more units out there have the same problem.

The problem is that,in addition to the current path through the paralleling solenoid mounted in the engine compartment, there is a sneak circuit that ties the chassis battery to the house battery. Under the right circumstances, battery charging current may get directed via that sneak circuit through wiring under the dash right in front of the driver. This all appears to be 16/14 gauge stuff, with the potential to cause a fire in the underdash wiring.

As you can see in the photo below, I am probing the voltage on each side of a inline fuse holder in the modified wiring that Jayco added to control the paralleling solenoid. And without the fuse being present, I am getting battery voltage on both sides of the fuse holder. At the time the picture was taken, the chassis ignition was on, and the heated mirror switch on the driver door above the mirror positioning switches was turned on.

When the heated mirror switch is turned off - one of the voltages goes away.
When the house battery is disconnected - the same voltage goes away.
When the ignition is turned to off - the other voltage goes away.

Another symptom of the problem is that the little led on the mirror heater switch is always on, regardless of the position of the switch. When the house battery is disconnected, the little led goes off. I've seen other posts in JOF that question why the led indicator never goes off - and that is why I believe that the problem is not unique to my vehicle only.

How many folks out there have seen that the heated mirror switch led is always illuminated?

[craigav]

Mine doesn't have that issue. However here is a schematic that may apply to yours (this is 2013 but is common for a lot of year models).

Hopefully this will help.

One other thought that you should be aware of, when the key is in the "ON" position, there is power to both sides of many of the circuits, just as if you had pressed the AUX START button. I wonder if the solenoid is actually working on yours.

~CA

[dc_mystic]

Originally Posted by craigav

Mine doesn't have that issue. However here is a schematic that may apply to yours (this is 2013 but is common for a lot of year models). The only thing I could think of that matches what you are describing is if the AUX START switch has the two terminals on the left (in the schematic) tied together. There is also a Diode adapter for the radio so it can run off of house or chassis battery and I think it is tied into my steps as well which isn't shown on the schematic. Anyway, hopefully this will help.

One other thought that you should be aware of, when the key is in the "ON" position, there is power to both sides of many of the circuits, just as if you had pressed the AUX START button.

~CA

Thanks for the schematic. I did see a copy of the schematic on another thread at JOF.

You bring up a good point about multiple power paths - I'll have to investigate the porch light switch as a possible path.

I believe the AUX START button is wired/working correctly. The switch is working like a double throw switch with power to the solenoid coming from either the house battery or the OEM ignition circuit.

When the chassis ignition is off, pushing on the AUX START button allows the house battery to energize the solenoid, connecting the chassis and house batteries so that you can start the engine.

When the chassis ignition is on and the AUX START button is in its normal position (not depressed), current is provided from the chassis ignition circuit via the yellow/pink wire, flows through the button, and that way the chassis battery drives the solenoid - that is how the chassis alternator gets a current path to charge the house battery.


I also tested the solenoid while charging the house battery from the AC converter while the engine is off. When the solenoid is engaged, the chassis battery jumps to the 13.8 volts that the house battery charger is running at.

[pconroy]

Like craig, I have heated mirrors and don't have that leakage/path. My mirror LED is not on. In fact, I'm not sure I have an LED. If I do, it's never been on.

[craigav]

I shortened my original comment, as I had thoughts that maybe I was on the wrong path.

In any case, does the relay engage when the key is on? If so then both batteries should show very close to the same voltage. ~CA