Coachmen Mirada 2004 House Battery not charging from engine

The problem is probably the same relay/solenoid used for the AUX Start circuit. I have the tech info for my coach, Intellitec Mini Gas BCC. Don't know what model Coachman used but many builders used that same hardware. I'll send a PM with the PDF I have.

What the document states concerning engine charging the chassis batteries:

A. Auxiliary battery does not charge.

1. The isolator relay may not be closing. Operate the engine at a high idle for at least twenty (20) seconds and check the chassis battery voltage. The voltage must be at least 13.3 volts before
the isolator activates. Check the alternator, if the voltage is less than 13.3 volts.

Check for voltage on the coil terminal of the isolator relay. This voltage is available on J1-5. If there is voltage on the coil, replace the printed board. If there is voltage on the coil, check for
voltage between the main and auxiliary batteries. If the voltage is more than 0.1 volts replace the relay.

Not knowing which solenoid is which makes troubleshooting a bit difficult. If the isolator solenoid coil is good you can hear it click when the AUX Start switch is activated.

Golden_HVAC wrote:
THat happened with two of my motorhomes, and I installed a new relay. I did not bother to locate the original factory one the last time (it is buried in a box with many large wires) but instead just hooked up a new one that does the job, the factory one with it's worn out contacts still is in there providing some charge ability.

Thanks
My problem is identifying the circuit and relay.
Mike

THat happened with two of my motorhomes, and I installed a new relay. I did not bother to locate the original factory one the last time (it is buried in a box with many large wires) but instead just hooked up a new one that does the job, the factory one with it's worn out contacts still is in there providing some charge ability.

I used a forklift relay #6C017 http://www.grainger.com/product/WHITE-RODGERS-DC-Power-Solenoid-6C017?searchQuery=6c017 from Graingers.com

I hooked up some #4 wire from the alternator output to the relay input to the battery supply +12 wire. This transfers the highest possible voltage (alternator output is about 14.5 volts, VS the 13.5 volts near the engine battery) directly to the coach batteries.

Fred.