Coleman 7335(?) Series Compressor Suddenly Stopped

[sgossman]

I started using this AC unit after about 2 years of no use. It started up great with no problems and was kicking out cold air great for about 3 days until the compressor just stopped in the middle of cooling.

I thought at first it was because it reached the target temperature but it was too warm in the room for that. No matter what settings or how low I set it I can't get the compressor to start again.

The fan works fine and I already checked all the capacitors and they are working (holding charges) as well. The fuse in the thermostat appears intact and the unit is not tripping any breakers.

I'm kind of stumped as to what else it could be. Only real suspect I have left is the start relay and apparently the exact type isn't around and I need to use some sort of replacement model I'm not sure of. Perhaps it could be one of the boards but I'm not entirely sure how to test those or what levels I would want. The only maintenance manual I've seen seems to require a specialized device to test various aspects of the unit.

I believe its part of the 7335 series but the model number has since worn away. Another number is 6799A381.

[sgossman]

mchero wrote:
Do you have an energy management system?

No, as far as I know. Older trailer and has no means to enacting any sort of energy efficiency or scheduling.

[mchero]

Do you have an energy management system?

[sgossman]

Well I got the new relay with no change. The universal replacement had multiple leads so I tried hooking it up according to wiring diagrams with no change so tried swapping them around, no change then either.

So I am fairly confident its not the relay but I'm not sure what else it could be except from what I read the control board or the compressor. Would be surprised if it was either because they were both performing great until the compressor shut off right in the middle of working fine.

Fan works great when I turn it on. When I set the thermostat to just COOL and ON the fan runs then as well but the compressor doesn't start. If I put it on AUTO the fan nor the compressor starts.

I think its significant when on AUTO not even the fan turns on or seems to attempt to run the compressor. It makes me think something that would give those commands is not working properly. I suppose it could be the control board despite it looking pristine, which I had some way to test it and what results I should be looking for.

I really wish there was some temporary bypass I could try to just tell the compressor to turn on regardless of other signals to see if it will even run.

[sgossman]

that's good to hear because I ordered this part, I'll just have to figure out which leads to use since it has quite a few more than the exact part.

https://www.ebay.com/itm/123744887539

Checking the compressor leads with a meter was going to be the next thing I do.

Oh, here is a picture of the current relay for reference.
https://i.imgur.com/rFMHBaQ.jpg

[wa8yxm]

If it is the starter relay (actually the run relay) there will be no voltage on the compressor leads.

Most any relay capable of operating a motor at 20 amps 120 volts will work. it may not fit on the board (you may need to "Remote" it with jumper leads.
But any relay designed to run a 2 HP motor should work.

Might be able to use a smaller one (I tend to use components on the "Heavy duty" side of life to avoid overload)