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Old 01-28-2020, 05:51 PM   #1
Junior Member
Brand: Thor Motor Coach
Model: 31S
State: California
Posts: 2
THOR #14831
Battery Disconnect Switch stuck to "On"

Hello all,

I have a 2018 Thor 31S. While trying to locate what I thought was a parasitic drain, I was inspecting my battery compartment to find that both of my parallel cables were extremely loose.

While tightening those connections, I inadvertently touched another piece of metal. I got a very small zap and then realized I still had the house batteries connected. I went to the disconnect switch and it isn't working. (It worked five minutes earlier)

All of the power in the house is working. I tried flipping the breaker in the battery compartment. I went to the disconnect switch to look for a fuse; I found one fuse that was fine.

I plugged in the coach to shore power so the batteries dont go dead. I used my multi meter and the charging is fine.

Is there another fuse or reset button am I missing somewhere so I can restore the disconnect switch?

Thanks in advance

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Old 01-28-2020, 06:31 PM   #2
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16ACE27's Avatar
Brand: Thor Motor Coach
Model: ACE 27.1
State: Florida
Posts: 3,837
THOR #7035
Realize that the actual switch you touch is not the connect/disconnect switch/solenoid that actually does the connecting/disconnecting: it is a remote operation switch that controls a 2 position solenoid that actually makes/breaks the connection. I'm not familiar with the specifics of your coach, but generally the switch you touch momentarily applies power to one of two electromagnetic coils that physically move the switching part to either the OPEN or CLOSED position and leaves it there.

The fact that you can't get it to open tells me that the power going to the remote switch may be bad, or it could be the physical connect/disconnect switch, or the wiring in between to the OPEN electromagnetic coils.

I'd start with a voltmeter at the switch your finger pushes.

Ted & Melinda
2016 ACE 27.1
2016 Chevy Sonic Toad
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Old 01-28-2020, 06:48 PM   #3
Senior Member
TurnerFam's Avatar
Brand: Thor Motor Coach
Model: Palazzo 33.3 34'bunkhouse
State: Alabama
Posts: 2,063
THOR #4735
probably, when you got 'zapped' you were simply making a connection between the positive and negative post of the batteries - which had nothing to do with whether the 'house' was connected, or disconnected.

because the 'house' items now work, you certainly have power coming thru the system as it should be.

because you can't now 'switch off' the house items may have to do with your 'zapping' moment - it may have temporarily set the solenoid/RV Custom Products device in a 'fixed' position. It works via an internal magnet - which creates a 'momentary' switch, to land at either one side, or the other, when you 'switch' the switch.

I would suggest that you disconnect the battery cables again, wait 30 seconds, then reattach. You may still seem some arcing - that's normal, even when you think you have all loads turned off.

you may then find that your switch and solenoid/RV Custom Products device is working correctly again.

try it, it can't hurt...
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Old 01-28-2020, 09:14 PM   #4
Senior Member
Brand: Thor Motor Coach
Model: Hurricane 31S
State: Texas
Posts: 1,688
THOR #6411
There is a 50 amp circuit beaker in the rear of the battery compartment that protects the relay and 8 ga wire to the relay. There is also a 5 amp fuse around the relay to prevent the switch being held down too long and burning-out the switching solenoid for the relay.
Jim & Roy Davis
2016 Hurricane 31S
1961 Rampside in tow
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Old 01-29-2020, 02:27 PM   #5
Senior Member
Brand: Thor Motor Coach
Model: 2013 ACE 30.1
State: Alberta
Posts: 1,012
THOR #2631
I believe 16ACE27 has the correct focus on this one. If the latching relay is “on” and won’t release then I would suspect the fuse that powers the door switch that operates or releases the latching relay first. If you have the RV Custom BCC (black box in the engine bay driver side; usually mounted near the inside cap front); the fuses for controlling the coach and chassis latch relays are inside the BCC. If you have the BIRD or BIM systems then I don’t know where the control switch fuse is located. A call to Thor may provide the likely location though.

If it is not the latch relay control switch power fuse, it could be the latch relay itself has failed in the on position. Using a voltmeter to monitor the control pin(s) on the latch relay would confirm if the on/off switch signal is getting to the relay.
javelin is offline   Reply With Quote

battery disconnect, drain, reset, switch

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