92 Fleetwood Bounder only starts with aux boost

All connections clean and tight? Cables good? Have you tested starter?

Verify connection on the chassis battery.
Check connections between the chassis battery and the battery control center.
Turn key on, does the dash indicator lights come on?
No, Operate the battery disconnect for the chassis battery. Shut it off and then back on, once or twice. Possible the battery disconnect has failed.
What chassis? Ford or Chev?

Check the connectors, and the battery cells on the engine battery.

enblethen wrote:
Verify connection on the chassis battery.
Check connections between the chassis battery and the battery control center.
Turn key on, does the dash indicator lights come on?
No, Operate the battery disconnect for the chassis battery. Shut it off and then back on, once or twice. Possible the battery disconnect has failed.
What chassis? Ford or Chev?

No lights come on. I will check connections again but seemed fine. Tried the switch several times. Ford chassis

AUX button uses the COACH battery to start the engine. HOW do you know the CHASSIS battery is good and fully charged? Doug

MountainAir05 wrote:
Check the connectors, and the battery cells on the engine battery.

I suppose even though battery is fully charged could be bad? To test I could jump it off my truck correct? That would tell me for sure.

dougrainer wrote:
AUX button uses the COACH battery to start the engine. HOW do you know the CHASSIS battery is good and fully charged? Doug

Correct understood. Put a charger on it and is at 100%

Did you find the battery control center? normally driver's side under the hood.
Check for voltage at battery disconnect for chassis and follow the power. There maybe a tripped circuit breaker.

enblethen wrote:
Did you find the battery control center? normally driver's side under the hood.
Check for voltage at battery disconnect for chassis and follow the power. There maybe a tripped circuit breaker.

I’m new to rv and learning as much as possible. Did find control center have cover off. Battery disconnect is that the same as the solenoids in bat control center? Can I check power there by connecting meter to both big post?

Make sure your battery terminals are clean amd tight. Our 96 Southwind will not start if there is a little corosion on the terminals.
Take them off and clean them, don't just look at the terminals to see if they're clean.