Originally Posted by Diesel75
Yesterday it worked, today it only puts out warm air. Is there anything I can do to fix it??
If it is a heat pump, there could be 2 trouble spots:
• your start capacitor (smaller one) and PRCT (motor start device) are bad and need to be replaced. NOTE! They should only be replaced with ones of identical specifications
• If a heat pump, the reversing valve solenoid is bad, resulting in your A/C unit being stuck in heat pump mode (ALL heat pump units are in heat pump mode by default. The reversing valve solenoid must be energized by the control board to function as an air conditioner)
Notice a slight burning smell?.......... probably your capacitor.
Be sure to have the A/C breaker OFF when testing the caps.
BTW: they are located on the upper unit under the shroud on the curb side of the A/C unit. Remove the rectangular plate you will find there and the caps are right behind it.