I have a Rheem furnace and the low speed fan continues to stay on after the furnace has cycled off. When I disconnect the red wire (low speed wire), the furnace runs normally. I would imagine the switch for the low speed is open. Is the switch controlled by the IFC? Does the IFC need to be replaced. The furnace runs as normal with the red wire disconnected, should I continue to run the furnace this way?

A fan control relay or a fan and limit control is you problem.

A fan control relay or a fan and limit control is you problem. Look on the wiring diagram on the blower door for location of parts. OR see the sticky notes in the beginning of this board.

I think I found the relay that is giving the problems. Are those relays soldered to the ifc board or do they pull off? It looks like they are soldered. Where would I buy the relay? I found a place that stocks these relays but they do not ship to Canada. I have taken off that red wire so that the fan doesn't run all the time. Is this safe to run this way until I get the relay?

OK to run with red off.

You are going to have to buy the circuit board. Those type relays are not available or easy to do. Sorry.