Battery disconnect or isolation solenoid? HELP!

In your picture you can see 2 large nuts and two small nuts, there should be 12+v across the two large nuts if it is working if only 12+v on one lug it is not engaging. Also check the voltage on the small nuts one should have a 12 v input to the solenoid. You can always jumper the 2 large connection to use the MH for your trip until you get a new solenoid.

Gjac wrote:
In your picture you can see 2 large nuts and two small nuts, there should be 12+v across the two large nuts if it is working if only 12+v on one lug it is not engaging. Also check the voltage on the small nuts one should have a 12 v input to the solenoid. You can always jumper the 2 large connection to use the MH for your trip until you get a new solenoid.

Is this the right part to replace if my house batteries are NOT charging from the alternator and if I don't hear any click when I push the battery boost button on the dash of the coach?

Also, I've read you can get one from autozone...how do I know the right part number that is compatible?

Gjac wrote:
In your picture you can see 2 large nuts and two small nuts, there should be 12+v across the two large nuts if it is working

Unfortunate wording.
You should see 12V ON both lugs if it is working. (Exactly the same voltage.)
Seeing 12 V ACROSS the two lugs means something quite different.

Before you get anything new in parts, make sure your ground return is good. Connect from the negative on the house battery to the negative on the coach battery with a jumper cable and just make sure that part is OK. A loose negative will prevent anything from charging.

With just the negatives connected, start the engine and then see what the voltage is at the house battery.

Artum Snowbird wrote:
Before you get anything new in parts, make sure your ground return is good. Connect from the negative on the house battery to the negative on the coach battery with a jumper cable and just make sure that part is OK. A loose negative will prevent anything from charging.

With just the negatives connected, start the engine and then see what the voltage is at the house battery.

They charge on gen and shore...so I think that side of things is good...

The solenoid in the picture is the disconnect solenoid and has little (nothing) to do with charging off the engine.
That bottom picture references a service manual- try to find it.

Yes, short term, you CAN "jumper" the solenoid.

But, do NOT use a jumper wire. If either end of the jumper were to come off and tough metal, you would have a DEAD SHORT from one of the batteries.

Safe way is to label the wires on one large lug and ADD THEM TO the wires on the other large lug. Return then to their original position when you want them separated again.

Chris Bryant wrote:
The solenoid in the picture is the disconnect solenoid and has little (nothing) to do with charging off the engine.
That bottom picture references a service manual- try to find it.

Now I'm even more confused...everyone else seems to be saying this does connect the two battery banks to charge them while driving (i.e. convo about jumpering the two large lugs, etc.) but you indicate that's not true???

can you measure the voltage on the two large lugs with engine running ?

do you have access, or trace the wires back

if that is the 'charge control' solenoid (and not working) one side will have alternator voltage and the other side will have house battery voltage

if both sides have the same voltage low 12.1, device might be working and problem is elsewhere
if one side is high aka alternator and one side is low, then that is the jump start / charge control and it is NOT working
so check the voltage across the two small wires, it may not be getting the command turn on power

the BCC (battery control center) are a know problem, that does fail
usually the control board or one of the fuses on the board,

the house battery system disconnect
disconnects the batteries from the RV systems, meaning NO power to the RV lights etc. NOT to be confused with the charge control/jump start relays