I have a heat pump with an older model thermostat. I just moved in here and the heat pump was already here, although it didn't seem to be properly taken car of at all. It still blows warm air when it is needed and works great as a central air conditioner, but the blower fan doesn't cvut off like it should. I can usually flip the 'fan' switch from 'auto' to 'on' and back to 'auto' and it will cut the blower fan off, I don't know why but it does. Here recently however, the switch flipping trick hasn't been working. The blower fan runs constantly, blowing fairly cold air through the house until the thermostat kicks the heat back on. Any help?

Sounds like a bad relay switch to me I don't know much about central air units but I know a good amount about relays hehe

I had the relay replaced today and it fixed the problem. I thought it would be the relay from what I had read, but thanks for input.