Have a heat pump not blowing cool air. Checked the unit and the exhaust fan is not operating. Any ideas?

Check the fuse for the fan. My heat pump blows the fan fuse once a year. If you have an electrcial tester use that, if you don't just replace the fuse (a few bucks) if it contiues you will need to have it looked at.

is the compressor coming on or is the entire outside unit dead? if nothing is working outside, check the breakers and disconnect first. next item would be the contactor switch and then check the capacitor(s). if it has two caps, one is for the fan and one is for the compressor. if it only has one cap with three poles it controls both the fan and comp.

best guess is one of those items. um, heat pumps also have another circuit for defrost but i don't think that's in play here.

ok, see if it has two capacitors. turn the unit off and pull the disconnect, (turn the power off). take off the service panel for the electrical controls for the outside unit. capacitors are silver can things or black/brown plastic things with wires coming from them. see if you have two of them. if so it may be the fan cap. if it's bad it may be misshapen or even cracked. if you determine that's the problem, use insulated needle nose pliers to remove wires, remembering where they go, (make a diagram). go get a new one and replace. be careful with capacitors. they hold a charge even with power off.