A/C won't stop

[Niles]

Got a issue, we left with a/c running, came home turned them off. Had the tv on and I keep hearing a noise, thinking my neighbor is running his air compressor. I finally go outside and hear it's my a/c running. Well crap I forgot to turn it off. Nope thermostat is set on off. My a/c compressor is still running, only way I can turn it off is by turning off breaker. I'm not a real smart person, but this ain't right. Next day thinking maybe something had froze up try it again, same thing. Up on the roof goes one irate camper, take the cover off, have DW hit the switch and compressor starts running but fan doesn't. So folks is it a bad motor that's causing my problem or something a little deeper. Just sitting here scratching my poor bald head. Thanks for any input.

 

[carl.swoyer]

Check your communication cable for corrosion. Looks green on the contacts . it runs from the thermostat to the ac.

Carl & Christine, 2012 Landmark Rushmore, 2005 Silverado crew cab lt 8 foot bed 6.6 lly /Allison -custom dual exhaust-198000 miles !

 

[mlpeloquin]

It is not a bad motor. The motor is running because a controller or something in between is telling it to. The thermostat tells the electrical interface that turns the motor on to turn it on. So it is electrical, but probably not the thermostat.

 

[Niles]

Checked all wiring, do not see any issues of corrosion, took wiring apart and looked at both ends. Fan motor on top does not run,compressor does engage and run. So I'm back to square one. I just don't understand why the compressor will keep running when we turn the switch off. It has to be turned off at breaker. It's looking like a trip to Leon's when i get back, lifes rough when you have to go to Shipshewana for repairs.

 

[danemayer]

Hi Niles,

Inside the coach, above the air conditioning return grill, there's a gray metal box with several connectors. The thermostat signals stuff in that box whether for furnace or for air conditioning. I'd guess there's a 120V AC relay in that box that powers the compressor, and a separate relay for the A/C blower.

My guess is that either the relay is stuck, or there's something shorted across the contacts.

Be careful working inside the gray box. You'll be standing on a step ladder or ladder and don't want to touch something live while on a ladder.

 

[Niles]

I've checked all I can and see nothing wrong. Wiring seems intact from thermostat to a/c unit, all wires secure, checked fuse, looked at all connections. It seems like I may have a fried board. Thanks for all the advice. Will be going to Leon when we get home.