Why is the fan constantly running on my furnace?
When your thermostat is set to AUTO, your furnace fan should blow only when your furnace is in the middle of a heating cycle. But if your fan runs constantly, regardless of whether your furnace is heating, that’s not normal. There’s a shorted thermostat wire. There’s a shorted wire at the fan limit switch.
How does a furnace fan limit switch work?
To put it very simply, the furnace fan limit switch is a control that tells your furnace’s fan when to turn on and off. So, when the furnace isn’t on, it tells the blower not to operate (and send cold air into your home) and when the furnace is on, it tells the blower to turn on and start circulating the warm air.
When do you turn off the Furnace Fan?
So, when the switch is working correctly, your furnace fan should turn on several minutes after thermostat calls for heat and turn off several minutes after the heat cycle ends. But if the furnace fan runs continuously, regardless of whether the furnace is heating or not, your furnace fan limit switch is either:
Why does my electric heater fan not shut off?
This comes directly from the ignition switch on the green/yellow strip wire so it looks like the switch is failing to disconnect. Try pulling fuse #20 in the battery junction box. This is a 50 amp square fuse that will be hard to remove.
Why does my furnace blower turn on and off all the time?
But since temperatures inside the heat exchanger should stay relatively stable when the furnace burners aren’t on, your blower fan shouldn’t be needed at all. So if your furnace blower is turning on and off when the furnace isn’t in a heat cycle, it usually means the fan limit switch is defective.
Can a car fan still run after the engine is turned off?
Then you notice the engine cooling fan is still running even though the car is turned off. It is ok for the engine cooling fan to keep running for a few minutes after turning off the car. Your car fan will run for a few minutes after you turn off the car then turn off. This is normal in many vehicles, such as BMW or Mercedes-Benz.
So, when the switch is working correctly, your furnace fan should turn on several minutes after thermostat calls for heat and turn off several minutes after the heat cycle ends. But if the furnace fan runs continuously, regardless of whether the furnace is heating or not, your furnace fan limit switch is either:
This comes directly from the ignition switch on the green/yellow strip wire so it looks like the switch is failing to disconnect. Try pulling fuse #20 in the battery junction box. This is a 50 amp square fuse that will be hard to remove.
Why does the fan shut off when I Turn Off the ignition?
Try pulling fuse #20 in the battery junction box. This is a 50 amp square fuse that will be hard to remove. If the blower then turns off the ignition switch needs to be replaced. when I went out and turned the fan control switch nothing came on. I turned the ignitionon and the fan on it came on. I turned off the ignition and everything shut off.
Why does my GM car heater not shut off?
In some cases in cold weather the blower motor may not run, or if it does, it may not shut off when you turn off the vehicle. The TSB applies to the following vehicles with automatic temperature control: GM has identified the blower motor control module as the cause for the failure.