The reason a heater fan is staying on may be an issue with the switch. It is possible the switch is stuck open. It may be resolved with a good cleaning of the contacts on the switch, or replacing the switch itself.
If you are talking about a wall switch for the heater, check to see if the heater has its own internal thermostat or switch as this might be in the off position and not allow the heater to turn on. If you are talking about a switch on the heater itself, then yes in all probability the switch is not working.
Where is heater control switch
Have you cleaned the filter? Ken
Where is the heater relay switch on a 2005 MalibuRead more: Where_is_the_heater_relay_switc
There is no Logical reason to do this. There is an off switch too btw
IT turns the heater on and off!
It could be the high speed heater motor relay is stuck on or the switch itself is broken.
To turn on the heater in your house, locate the thermostat and set it to the desired temperature. Then, switch the heater on using the power button or switch. Wait a few minutes for the heater to start producing warm air.
It sounds like it might be the switch or an overheated connector. Finding it might be difficult.
A restricted/plugged heater core can do that. Try flushing the heater core.
Your heater switch may not need to be replaced. The heater high position is controlled by a fuse under the hood. Until you find the fuse and replace it, your new switch will not work. JRR.