Coleman Mach No Start in Auto

[Wxman]

Hello
Coleman Mach 48204-669 in my 2021 274CKDS. Controlled via the mini Bmpro.
Worked in AM in MI. Five hours later in IN it would not start in Auto Cool. I would get a humm and thunk and then nothing. (I first thought the EMS had tripped).
Works fine in Cool, both on low fan and high fan. Thermostat reading seems correct and all.
I haven’t troubleshot much because not sure where to start.
It seems to me the system is calling for start as it tries to do something. AC works fine in Cool just don’t know why it wouldn’t start when called to in Auto Cool,

[TowPro]

in auto cool (if you have a furron) your trying to start both the FAN and compressor at the same time. If you use Cool, High or Low, the fan will stay running and when thermostat calls for cooling you are only starting compressor because fan is already running. When its real hot out my F150 power boost 2300w generator might not start the AC in auto cool, but pick cool high or low and it works every time.
but I see you have a MACH. my last MACH was an 8 in a pickup camper with controls on the ceiling so not much help I guess.

[Wxman]

Interesting. Probably similar. We had just set up and it is 30 amp. EMS nor circuit breaker went off. Other AC did work fine. Yes, only using one at a time.
Anyway, after some head banging and no answer I tried it late this afternoon and it has been flawless. I will hold off worry until it happens again.
Thanks

[Topperace]

Do you have a soft start device in that AC? Also check the park voltage at the pedestal during that period…maybe getting low, but not low enough to trip the EMS. I had that happen at Lake Tahoe park, AC just wouldn’t run as voltage was too low.

[Wxman]

No soft start. Voltage could easily have been a player. Hot Friday afternoon, park filling up. Hardwired Progressive EMS said OK, I think I remember a 114V flash on display at one time and I didn’t keep checking at that moment as I switched to other unit OK.
Looks like maybe perfect storm of little things at that moment. Still working now.