AC unit won't turn on: both inside blower fan and outside fan unit won't turn on. It is as if I had gone to the circuit breaker and cut the power to the whole HVAC system, but I didn't. I've been searching around and saw that in most cases, either the inside or the outside unit won't turn on, but I have not found a case where both won't turn on.
The outside unit has a disconnect box that contains no fuse. I've double checked that the rabbits didn't somehow manage to take the connector piece out...
I've also replaced the old mercury-based thermostat with a new digital, battery-powered thermostat, which didn't help. I can hear the clicking sound it makes to turn on the AC, but nothing else happens.
It was working fine 5 days ago. I turned it off for 5 days straight, and now it won't turn on again.
I'm trying to get an HVAC pro to come and take a look, but they're booked until next week. Is there anything else I can check in the mean time?
EDIT: I'd like to open up the access control panel to check for fuse locations, but I cannot figure out how to do so. Here's a picture of what I assume to be the panel door. I've tried prying it open from all 4 sides with a flathead driver. It also doesn't slide in any direction. Any suggestion?
Additionally, I've verified that there is electricity in the unit. There is voltage in that the exterior white wire going from the box to the thermostat (see picture) and there's also voltage going through the disconnect box and into the outside fan unit...
I was able to take the control panel door off, and found that it's getting no electricity. As you can see in pic1, the exterior white wire is live and it goes in the little box with the black push switch to the left of the picture. However, in pic2 the three internal wires (green, white, and black) going out of the box are not live.
Pic1 - electricity going into the little box
Pic2 - no electricity going out of the little box
Additionally, the red status light that used to be on all the time (which I didn't recall till now) is now off.
Pic3: red status light no longer on.
So what is this little box and could it be the cause?