Woke up this morning to this message from the thermostat:

enter image description here

I can click that message away and it then it appears to call for cool. The air handler turns on but no cooling.

The outdoor unit shows no signs of life. Not like compressor struggling to turn on, but nothing. Not even a click of some kind.

The breaker is on, the voltage at the disconnect is correct. Upon taking the panel off (which is as far as I can comfortably go), I saw this (see white bubble):

enter image description here

Can anything be deduced from that?


It may just have been a loose connection. With the disconnect off loosen the lug and remove & inspect the wire. If the lug and wire are not burned off you can clean them up and torque the lug(you have enough wire to trim and strip a new piece if needed). I see this quite often many times at the disconnect. Checking the lugs at the disconnect (on the load side) if they are loose it would be a good idea to kill the feed to the disconnect and torque them, once everything is snug turn the disconnect and feeder breaker back on.

If everything fires up the loose connections were the cause, if it won’t start it may have blown a fuse but I don’t normally find blown fuses with loose connections. I have seen much worse that when properly cleaned up and tightened have worked fine, I would suggest giving it a try, if it starts know you just saved a c note at least. If it won’t start after that then looking at the starting cap and contactor would be the next steps also a diy project you may want to do.

  • The connection is actually solid. If it were a cap issue, wouldn't I see some signs of life?
    – Wynne
    May 24 at 21:36
  • You have a point of high resistance thus the small amount of insulation damage. If that is the contactor the wire is connected to the cap and the contactor may be bad,,, when caps fail the motor takes more current to start if the cap is putting more strain on the contacts they can start arcing on 1 side or both, the worst contact gets most the heat until it won’t do anything. A pic straight on will show if this is the contactor and probably show carbon flash marks if the contacts are failing, this is why I followed up with the cap and contactor after tightening because I only have 1 view.
    – Ed Beal
    May 24 at 22:35

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