At some point in the recent past, my Heater/AC has started acting differently. In the past when I had it on auto, the temp would self regulate, and the blower would cycle through defrost vents, face vents, then floor vents.

It doesn't do that anymore...

I just figured out how to read the error codes from the control head, and I am getting an error on the left and right hand solar sensor (code 21 & 22).

My question is... would a bad solar sensor effect the cycling of the vents? I figure it might effect the ability f the system to auto regulate the temp, but not sure.

I replaced the heater core this summer. Could I have mistakenly unplugged something? I just pulled the radio and tried to feel to see if all of the connectors are all plugged in. As far as I can tell, everything is hooked up.

Thanks!