Coach and chassis Battery disconnect switch

[Waiter21]

I have a "New to me" 1999 Southwind. I'm slowly working my way through the small list of things that don't seem to be working, or I don't understand how they are supposed to work. I do have the manuals and although they are helpful, they don't have a lot of detail..

The question:

I see the two Battery disconnect switches above the door, one for coach and one for chassis.

When I toggle the coach switch, I hear a loud clunk of the solenoid, and I can verify it really connects/disconnects the coach battery as the coach lights go out.

However, when I toggle the Chassis switch, I don't hear any clicking or any sounds at all..

How can I verify that the chassis disconnect is really working????

Is there a disconnect solenoid for the chassis battery???

Should I be hearing a CLUNK of a solenoid????

NOTE - WOW, This is really a nice MH..... Every-time I go into it, I can't believe we picked this thing up for a song.....

[MisterT]

try starting the coach, if it doesn't, then you've disconnected it with the switch, and it works

[mojoracing]

You should definitely here a clunk when you toggle both the cutoffs.

[computerguy]

Originally Posted by MisterT

try starting the coach, if it doesn't, then you've disconnected it with the switch, and it works

Not always correct on Fleetwood products. Depending on the revision of the BCC it could engage the batts when you turn the ignition switch on.

[buzz57]

On yours/ours, yes you will hear the chunk for both. They are located in engine compartment on drivers side firewall. DISCONNECT ALL BATTERIES BEFORE OPENING COVER!!
There are connections that WILL contact the cover and arc out in removing it. Inside you will find a rats nest of wiring,solonoids (3) etc. 2 of the solonoids are constant duty-the chassis and the engine and a temp duty for the aux start the switch under steering wheel left side. It joins both systems together (momentary contact) to allow starting if engine/chassis goes dead. My guess is one of them is frozen from lack of use. I don't think they are serviceable but you'll see when you get in there? Good luck!

[Old Bounder]

Originally Posted by buzz57

On yours/ours, yes you will hear the chunk for both. They are located in engine compartment on drivers side firewall. DISCONNECT ALL BATTERIES BEFORE OPENING COVER!!
There are connections that WILL contact the cover and arc out in removing it. Inside you will find a rats nest of wiring,solonoids (3) etc. 2 of the solonoids are constant duty-the chassis and the engine and a temp duty for the aux start the switch under steering wheel left side. It joins both systems together (momentary contact) to allow starting if engine/chassis goes dead. My guess is one of them is frozen from lack of use. I don't think they are serviceable but you'll see when you get in there? Good luck!

Just to correct some of the terminology used in this post...

• The two Disconnect solenoids are mechanically latching (actually magnetically latching) solenoids.
• The one aux-start solenoid (also designated as the ISOLATOR/CHARGE solenoid) is definitely a continuous duty solenoid, NOT a temporary duty solenoid.

Further, it is not necessary to disconnect the batteries prior to opening the BCC box cover if proper caution is observed when doing so. It is often necessary to have power to the internal components while doing any meaningful testing and/or problem isolation.

You should hear a clunk, and quite possibly chirping from your propane sensor when both the chassis and house disconnect switches are operated to the OFF position.

The simple "try starting" test suggested by MisterT would be valid for your vintage coach.

[ga traveler]

Originally Posted by Old Bounder

Just to correct some of the terminology used in this post...

• The two Disconnect solenoids are mechanically latching (actually magnetically latching) solenoids.
• The one aux-start solenoid (also designated as the ISOLATOR/CHARGE solenoid) is definitely a continuous duty solenoid, NOT a temporary duty solenoid.

Further, it is not necessary to disconnect the batteries prior to opening the BCC box cover if proper caution is observed when doing so. It is often necessary to have power to the internal components while doing any meaningful testing and/or problem isolation.

You should hear a clunk, and quite possibly chirping from your propane sensor when both the chassis and house disconnect switches are operated to the OFF position.

The simple "try starting" test suggested by MisterT would be valid for your vintage coach.

As usual OLD BOUNDER covered it very well. (and correctly) The only thing I would add is we were a fleetwood dealer at this period of time. The latching relay was lubed with a grease that hardened over time. The latching relays were put together with 4 screws. It is easy to disassemble and clean the dried grease. At least 60% of the time dried grease was the problem.
Also he is 100% correct in saying you can troubleshoot with power on the box, But you MUST be careful to disconnect the batteries and make sure the motorhome power cord is disconnected before removing the board and any parts. The first thing I would do is remove the four screws in the switch panel by the door. Unplug the chassis switch and and plug the wire into the house switch. We had many more push button switch failures than any other component.

[Waiter21]

On my list for good weather weekend...
tnks

[Waiter21]

I took the cover of the BCC and looked inside. I assume I'll need to remove the circuit board to get to the latching solenoids underneath.

I assume this job will require disconnecting both batteries (house and chassis) and also no shore power. i.e. make sure there is absolutely no power on anything before trying to remove the circuit board.

[Old Bounder]

Originally Posted by Waiter21

I took the cover of the BCC and looked inside. I assume I'll need to remove the circuit board to get to the latching solenoids underneath.

I assume this job will require disconnecting both batteries (house and chassis) and also no shore power. i.e. make sure there is absolutely no power on anything before trying to remove the circuit board.

Good plan.

Take some pictures of the board, with special note to where all the wires are plugged into the board, before starting removal. You can't be too careful in documenting your every move.

[ga traveler]

Originally Posted by Waiter21

I took the cover of the BCC and looked inside. I assume I'll need to remove the circuit board to get to the latching solenoids underneath.

I assume this job will require disconnecting both batteries (house and chassis) and also no shore power. i.e. make sure there is absolutely no power on anything before trying to remove the circuit board.

Correct! Before doing that, I would check the switches at the door.

[Waiter21]

I disconnected the coach and chassis batteries and unplugged from shore power. I verified there was no voltage anywhere on the MH.

I then disassembled the BCC, removed the solenoids and tested them, They were both OK. (Interesting how they work. they use a permanent magnet to hold the plunger in)

There was some corrosion on the circuit board that I cleaned while I had the BCC apart. but this wasn't my problem.

After reassembly, I got a voltmeter and measured the voltage at the disconnect switches. I had 12 volts on the coach switch (orange wire), but zero on the chassis switch (red wire)

I went to the BCC, measured the voltage there, and I had 12 volts on both wires. HUM....

I started looking around and found the problem by accident. Where the wire bundle goes thought the firewall (behind and to the right of the BCC), there were but splices. In the group of wires I knew came from the BCC, I I could see a red wire was pulled out of the but splice.

I jumped the red wire back to the but splice, and CLUNK - CLUNK the disconnect now works.

I re-soldered the red wire and put heat shrink on it.

When I closed up the BCC, I used a thumb screw and a blind nut plate to replace the bottom missing latch

[Blandry29]

There's nothing like that sense of satisfaction when you solve the mystery, fix the problem and everything works!

[Waiter21]

Bob, AND, it wasn't really a waste of time tearing the BCC apart, because now I know exactly how it works.

This Southwind is really a nice MH.....