Can someone help please? My heater for some reason is not working. It worked all Winter long but not now. It has a switch on the outside of the unit in the basement. I'm not sure what that is for. It has an on/off switch inside too. There is a metal coiled filter that can be rinsed but it does not seem to be dirty. The heater/cooler is about 6 years old.

Also, now my air conditioner froze up. Is that normal? We rinsed the coils in the unit outside, but it didn't seem dirty.

I fear you have to be a little more precise. This is not enough information other than for pure guesses!
What type and/or brand is your heater? Is there anything that functions or which you hear or see when you switch it on?

And re your aircon : is that combined with your heater in some way? Is it electrically connected ? (Same questions as to your heater )

Is it perhaps possible that both units have no AC supply ?

;)

They are electrically connected. It is a TEMPSTAR and it is possible I am low on Freon. When I turn the heat on it makes a tapping sound. I turned off my air to let it thaw and it is working again.