12 volt problems

[Old Bounder]

Originally Posted by YC1

Your description is a bit confusing and does not add up but it is a simple system.

With the engine battery disconnected and you turn the key it is bringing your house batteries in to play and hence you start the engine via that bank of batteries. That should answer your first question. But then you add "if the 12 volt battery is dead" why doesn't it start.

What battery do you mean.

Your system should be very simple. Two battery systems. One for the rv, one for the engine. If the rv batteries die, your engine should start via the engine battery. If the engine battery dies you should be able to start because a solenoid brings the rv batteries online when you turn the key. Sort the two batteries out and replace the bad one or ones. If over a couple of years just change the batteries and stop fussing about.

Obviously (YC1), you don't know how Fleetwood Bounder battery controls are wired.

Simply turning on the key does NOT energize the solenoid to connect the batteries. The solenoid only closes when charging voltage of >13.2v is detected. The solenoid can also be closed by pressing (and holding) the Aux Start switch while trying to start the engine.

[TQ60]

First, realize that BOTH batteries are in disconnect mode, zero volts present anywhere except to the momentary switches above the door.

Turning key does nothing, nor does any other action.

If coach batteries are below the voltage required to pull the start relay in, it will not do so.

The power for the battery controls is sourced from the coach batteries which are too low to work in this case.

Thus the starting battery is not connected, period.

Pushing the boost switch connects both battery systems together which will allow the relays to work and connect the battery, problem is the boost switch is momentary and mounted on the dash, the battery control switches are mounted above the door, requires helper to push one or the other.

[rsw1943]

Problem was a bad isolator seleniod.

[georgetown350]

I have a 1997 Bounder, (ford 460 chassis). When I disconnect the 12 volt engine battery, why does the engine still start????? With the 12 volt battery disconnected, everything still works. BUT if the 12 volt battery is dead, I can't start the engine... HELP

Problem was a bad isolator seleniod

Doesn't add up but know one said it had to....... congrats on the fix