Aux Start Switch Does Not Work

[raymondbirt]

I have a 2006 Itasca Sunova 34ft Gas Motor Home and a couple of times my Chassis battery would not start the engine after camping about 5 days. Both times I tried holding in the Aux Start Switch on the Dash and then turning the key to start the motor home and it did not help at all.

I really don't think it was making contact at all, it seemed like it was not hooked up or the switch was not making contact.

My question is what do I check first or has anyone else had this problem?

Thanks,

RB

[HenryPatterson]

First thing I would do is Check the fuse..Had one do the same thing and the fuse was popped! Replace the fuse and worked fine ever since..

[wolfe10]

Locate the RELAY/SOLENOID that the switch controls. Your coach maker can tell you where it is. With a voltmeter, it is a very quick and easy test to see if the relay/solenoid is bad or if it is not getting the signal from the switch:

There are two large lugs-- when batteries are not combined, they will have different voltage, one for chassis and one for house battery. When the Combine/Boost switch is on, the two large lugs should have the same reading, as the batteries are combined.

If voltage at the two large lugs is not the same with the combine/boost switch on, locate the small signal wire on the relay/solenoid. If there are two small wires, one is ground, the other is the signal wire. If only one small wire, it will be the signal wire and the ground is through the body of the relay/solenoid. Remove the signal wire from the terminal on the relay/solenoid. With the switch on, you should have 12 VDC between it and chassis ground. If you don't you need to check the switch and/or fuse and/or wiring.

If no voltage on signal wire, you can test the relay/solenoid by using a small jumper wire from either large lug (lug with higher voltage would be better) to the signal terminal of the relay/solenoid. Very little current is needed, so a small wire works just fine. You should head the "click" as the relay/solenoid closes and voltage at the two large lugs should be the same.

Brett

[justus2]

I think Wolfe 10 answered your question. I just had to replace my relay 2 months ago. can you hear a "click" sound when you engage aux switch? I can on mine if it's working. These things seem to go bad from lack of use--had to replace one also when I owned a class"C". Cost around $60 installed I think.

[Yak61]

Locate the RELAY/SOLENOID that the switch controls. Your coach maker can tell you where it is. With a voltmeter, it is a very quick and easy test to see if the relay/solenoid is bad or if it is not getting the signal from the switch:

There are two large lugs-- when batteries are not combined, they will have different voltage, one for chassis and one for house battery. When the Combine/Boost switch is on, the two large lugs should have the same reading, as the batteries are combined.

If voltage at the two large lugs is not the same with the combine/boost switch on, locate the small signal wire on the relay/solenoid. If there are two small wires, one is ground, the other is the signal wire. If only one small wire, it will be the signal wire and the ground is through the body of the relay/solenoid. Remove the signal wire from the terminal on the relay/solenoid. With the switch on, you should have 12 VDC between it and chassis ground. If you don't you need to check the switch and/or fuse and/or wiring.

If no voltage on signal wire, you can test the relay/solenoid by using a small jumper wire from either large lug (lug with higher voltage would be better) to the signal terminal of the relay/solenoid. Very little current is needed, so a small wire works just fine. You should head the "click" as the relay/solenoid closes and voltage at the two large lugs should be the same.

Brett

I think this on the close to the problem I am having.

I have a 2005 Fleetwood Jamboree "C" Ford F450. The last two months when I took the MH out of storage to exercise it, the chassis battery was completely dead (2 year old battery). 1st month removed battery to charge and noticed dash lights where on, and the engine would start without chassis battery? Today held the aux start switch and was able to start chassis off house batteries.

After an exercise drive, checked voltage and both batteries where the same 12.7 volts. Disconnected chassis battery and chassis starts without holding aux switch or chassis battery? I would think the house batteries would be isolated from the chassis until the aux start switch is depressed.

Am I looking for a switch, solenoid/relay problem? and could a bad switch solenoid drain the battery?

Any suggestions would be helpful.

Mike

[desertdeals69]

Is it possible that the wiring is reversed?

Does the house still work with the chassis battery disconnected?

If everything is wired OK it might be the solenoid stuck.

[Yak61]

Desertdeals

I do not think anything is reversed.

All house systems are working without the chassis.

Found the solenoid, with the chassis battery disconnected I started the chassis using the aux switch and house battery. Then after turning the engine off, hecked the disconnected cables at the chassis battery and they showed 12 volts from the house battery.

After a few minutes the solenoid must have opened, no voltage at the chassis cables. Do you think there should or could be a delay in the solenoid opening the circuit? I would think it would be only momentary while the aux switch is depressed.

Not sure if this is all related but when I reconnected chassis battey and started engine. Checked voltage 14+ volts on the chassis side of the solenoid but not on the house side. So it does not seam to be charging the house battery while the engine is running.

Would make me think the solenoid is malfunctioning? and could be the cause of the chassis battery being drained.

Does any of this sound logical, I am just not very familiar with solenoids and relays.

Mike