Auxiliary Start Problem

[Traveler78]

Just learned a valuable lesson about auxiliary start. Most RVs have them but when was the last time you disconnected the engine main battery and tried an Aux Start? We've RV'd for 16 years and never had to use the Aux Start. Tried it the other day with a weak engine battery and the Aux Start didn't work....it never switched over. Turns out the metal encased relay in the engine main power distribution box was bad (probably corroded internally from non-use). Getting a new relay and lucky to have found out in a non-emergency situation. Recommendation: Use your Aux Start on a random basis to keep the relay and system operational. You must disconnect or isolate the engine battery to get a good check.

[Gary RVRoamer]

You must disconnect or isolate the engine battery to get a good check.

Actually you do not. With genset off and disconnected from shore power, start the engine and check voltage at the house batteries. They should read in the 13.6-14.4 range if the Aux switch closed as it should when the engine is running. The Aux Start relay is the same one as allows house battery charging from the engine alternator.

[Hittntheroad]

I was thinking the same thing. I actually traced the battery cable from the house battery to the solenoid under the hood to verify where it was located. Figured out I could jump the house battery to the starting battery where they tie into the selonoid if need to if the selonoid didn't work. Will be testing mine.

[Hittntheroad]

Just checked mine. Disconnected the negative cable on the chassis battery. Turned ignition on. Nothing. Left the ignition on and pushed the aux switch. Dash ignition lights came on. I also have a dual battery switch for the house batteries so I can set it to have all 3 batteries if needed.