On my 2002 Jeep Liberty, I had lost the lowest speed on my heater blower and the blower also takes several minutes to start working after starting the vehicle. We have replaced the resistor and now have all speeds, but it still takes several minutes for the blower to start working.

the heater fan is dead. blower.
check the heater fan fuse for BLOWN.

Sounds like your starter is not working,here's a link on how to remove,take to Autozone and they will test for free,takes only a few minutes.To check for power at starter,get meter and it should read 12 volts.

look under the dash next to the blower motor there is a 6wire plug that is the resister look at that for burned connectors and on the board part look for a burned out section

this sounds like the heater motor resistor has gone bad and needs replacing.this controls the amount of voltage that goes to the blower motor to give you the different speeds.if it was the blower motor it wouldn`t have worked on #4 setting before stopping.this us located in the air box as it uses the air flow from the motor to help keep it from getting too hot,usually in the area of the motor and has about 5wires connected to it.

hi it is uncommon but does happen , that the blower motor jams. the best way to find out is to take the power leads that go to the heater motor and bypass them directly to a 12v supply. if it runs, thats a big headache out of the way.. the only other thing then is the dash switching itself. youve changed the rheostat under glove box i take it.. so its either power or controlled power or the unit itself..

maybe check the heater fan motor by hooking it direct to power and if it blows full power then it has to be the resistor or maybe the switch for the speed control is burned up.

If you mean that the heater "fan" only works sometimes, there is heater blower resistor mounted to the heater motor, (behind the glove box) and if it goes bad, you normaly have high speed only. These are common to go bad, and not expensive.

need to replace fan speed sensor located near the blower motor

The lower speeds are accomplished by running the power supply through various resistors that drop the voltage which makes the blower turn at different speeds. The lowest setting uses all the resistors to drop the voltage as much as possible to turn the blower as slow as possible. High speed uses no resistors so the blower gets full power and turns as fast as possible.

Since speed 1 and speed 2 use the speed 3 resistor to drop there voltage and speed three is not working as well my guess is the speed three resistor is burnt out in the device referred to as the blower motor resistor or blower motor speed control module. This is located near the blower motor and is held in place with 2 screws. There will be several wires and possibly two connectors plugged into it.

These are really common failures in many vehicles. The parts are usually available at your local auto parts store and they are typically not that expensive.

Hope that helped.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

it sounds like it may be the blower motor or resistor.