AUX Start solenoid ?

[monkey]

On our 95 class A our Aux Start light is on. I unplugged the solenoid power wire (the small yellow one in the pic) and the light stayed on. In the pic it would be the silver solenoid in the middle connecting the 2 battery solenoids,,, right? The solenoid is very hot. I'm guessing it's stuck "on" . I always use a jumper cable from one black solenoid to the other when stored so the shore power will keep both batteries charged. Whatcha think ??? Time to replace the solenoid? Thanks !!

(stupid phone,, sorry the pic is crooked...)

[3 Birds]

The solenoid should definitely not be hot. Couple of things to check:

1. There should be no voltage at the pull in terminal (the yellow wire from your description). If there is, this would indicate a problem with the start boost switch.
2. The solenoid should show 12v potential across the big terminals, indicating the contact is open. If there is a smaller voltage it would indicate the contacts are stuck closed (assuming no voltage in step one above.

Hope this helps.

Cheers, Gord

[monkey]

Thanks Gord. I have no power at the small wire, but yes power on both sides of the solenoid. I tapped on it, but guess its time to replace it. Thanks very much !!!
Monkey

[monkey]

Ok, I pulled the solenoid... It's "open" from the two large terminals that come from the two batteries... Why would it be getting so hot ?????

[Old Bounder]

Originally Posted by monkey

Ok, I pulled the solenoid... It's "open" from the two large terminals that come from the two batteries... Why would it be getting so hot ?????

I suspect that the yellow wire DID have power on it before you unplugged it. You did say the the aux start light was ON.

Power through the solenoid coil is the only way the solenoid could get hot.

I'm not familiar with your coach, so I don't know if that aux start switch is the only way the solenoid gets closed or not. Most coaches have a circuit called an IRD (or other ignition contacts) that also closes that solenoid to charge the aux batteries, from the alternator, while driving.

Evidently, your coach does not have the BIRD, Bi-Directional IRD, since you say you have to jumper the battery disconnects to keep the chassis battery charged (from the converter) while in storage.

I further suspect that your converter is putting out about 13.6V and that is being constantly applied to that solenoid, and could easily make it hot to the touch.

It's possible that someone replaced that solenoid with a NON-Continuous Duty solenoid. They will run hotter, and burn out quicker, than the correct, Continuous Duty type solenoid.

[monkey]

Originally Posted by Old Bounder

I suspect that the yellow wire DID have power on it before you unplugged it. You did say the the aux start light was ON.

Power through the solenoid coil is the only way the solenoid could get hot.

I'm not familiar with your coach, so I don't know if that aux start switch is the only way the solenoid gets closed or not. Most coaches have a circuit called an IRD (or other ignition contacts) that also closes that solenoid to charge the aux batteries, from the alternator, while driving.

Evidently, your coach does not have the BIRD, Bi-Directional IRD, since you say you have to jumper the battery disconnects to keep the chassis battery charged (from the converter) while in storage.

I further suspect that your converter is putting out about 13.6V and that is being constantly applied to that solenoid, and could easily make it hot to the touch.

It's possible that someone replaced that solenoid with a NON-Continuous Duty solenoid. They will run hotter, and burn out quicker, than the correct, Continuous Duty type solenoid.

Thankyou Very much for the reply. I went out today and checked again,, no power to the small yellow wire to the fuse block. BUT as soon as I turned the ignition key to "on" it had power... It should not the way I see it. So for now, I'll leave the small wires disconnected and taped up. The convertor on shore power only charges the coach battery,, the reason I hook up the one jumper, to keep the chassis batt charged as I sometimes use the dash radio. I have no problem hooking up a battery jumper cable while stored. Thanks again !!!!

[Old Bounder]

Originally Posted by monkey

Thankyou Very much for the reply. I went out today and checked again,, no power to the small yellow wire to the fuse block. BUT as soon as I turned the ignition key to "on" it had power... It should not the way I see it. So for now, I'll leave the small wires disconnected and taped up. The convertor on shore power only charges the coach battery,, the reason I hook up the one jumper, to keep the chassis batt charged as I sometimes use the dash radio. I have no problem hooking up a battery jumper cable while stored. Thanks again !!!!

Ah-ha!, You didn't initially say the ignition had to be ON. That's the way your coach is supposed to work. Winnebago also did it that same way for years.

Rather than install the IRD circuitry that I referenced earlier, they simply power the solenoid with the ignition signal so the alternator can charge the house batteries while driving. Simple and effective, but crude.

You will need to hook that yellow wire back up if you want to keep your aux batteries charged from the engine alternator while driving.

The solenoid should cool down when the ignition is off. If you think it is too hot, you can replace it with a continuous duty solenoid with a higher coil current rating, or get one with a 14volt coil, but I think what you are seeing is absolutely normal.

BTW - if your chassis battery is getting weak (and needing more current to keep it charged), your alternator may be putting out a higher voltage than necessary, which will certainly make that solenoid run hotter.

[monkey]

Ah,, now it makes sense ! I will hook it back up today and moniter it . I might end up replacing it. Thanks Very Much Bounder !!!!! Monkey