Why does my blower fan not come on in auto mode?

Why does my blower fan not come on in auto mode?

Everything goes as it should except when time for blower fan to come on. It doesn’t come on if in “auto” mode but if I put it in the “on” mode, the blower comes on and I have heat. I replaced the limit switch L170-40 and still have the same problem. There is another limit switch in the blower area L140-40.

What should I do if my car fan won’t turn on?

On modern vehicles, a bad sensor usually triggers the check engine light. Scan the computer for trouble codes, if necessary. If the fan fails to come on, first check for a fan blown fuse or triggered breaker. On older vehicle models, you may have a fusible link in the circuit.

Why does my HVAC fan not turn on?

This means there’s a problem between the board and the motor, or with the motor itself. If the terminal is not energized, then you’ll have to start moving “back” through the circuit. If the furnace is signalling for the blower to turn on, but the blower is not starting.

How to check a fan motor for faults?

Check a fan motor for faults. Fan motor with the thermo-switch lead disconnected and test lead connected to the battery. Look at the fuse box for a blown fuse. If the fuses are intact, switch on the ignition and use a circuit tester to find if there is current at the motor terminals .

Why does my fan run only in auto mode?

If the burner starts, the plenum heats, and the blower starts as it should, then you have isolated the problem back to the thermostat or its wiring. The fan will run and blow warm air but only in FAN or FAN ON mode – delivering heat – but NOT in AUTO mode. This is a bad temperature sensor in the unit; replace the fan limit controller.

On modern vehicles, a bad sensor usually triggers the check engine light. Scan the computer for trouble codes, if necessary. If the fan fails to come on, first check for a fan blown fuse or triggered breaker. On older vehicle models, you may have a fusible link in the circuit.

This means there’s a problem between the board and the motor, or with the motor itself. If the terminal is not energized, then you’ll have to start moving “back” through the circuit. If the furnace is signalling for the blower to turn on, but the blower is not starting.

Can a blower fan be turned on in cool mode?

If the Y terminal is energized, it turns on the a/c outside unit, but not the blower fan. Typical thermostats will energize the G terminal when in cool mode, or when the fan is turned to manual “always on” mode. It sounds to me like the G terminal is not being energized.

Is the a / C blower motor still original?

It just doesn’t cut it in the Georgia summer heat! – the blower motor turns just fine and doesn’t seem to have a lot of resistance to it, although the plastic fan portion itself is still labeled 2/99 so it is original. I’m not sure if the motor itself is original.

Where is the leak on the a / C blower?

The A/C was getting kind of weak, again, and I once again noticed a small leak at the back of the compressor on the bottom side of the manifold where the hi & lo lines bolt into the compressor. There is a little safety relief valve at the bottom.

Why does my Ford PowerStroke blower quit working?

Well the “NEW” blower motor is as weak, or weaker, than the original 13 year old Ford blower. That isn’t the problem. It’s been on the truck for 1 day and it’s going back to RockAuto. Today in the 90 degree heat, it decided to just quit spitting anything out of the vents altogether.