I have a 2001 vw jetta have a blower motor or fan

they unplug.

a resistor went bad for your blower motor.It is located by the blower motor on a circuit board.You can get the replacement resistor at Radio Shack and solder it in.This fixed my problem

a couple of things to check fuse check each fan.speed unplug the wire to the blower motor and check for power the blower motor resistor could be bad or blower.motor.

Not a VW expert here - but does the fan still blow on higher speeds ?
My first guess would be the fan switch or the resistor.
On most cars the compressor will run with or without the blower, but VW cars may get compressor power from the blower resistor.

The next time the blower fan doesn't want to come on whack it with a wooden hammer handle, if it starts you need to replace the blower motor the armature brushes are defective or sticking.

bearing in the blower mtoor is seizing, replace the motor before you loose the resistor as well.

Check the cover for the environmental cabin filter. It is located on the far right side of the cowling right below the right windshield wiper. There are a few torx screws that secure the cover and then it pulls out to reveal the cabin filter. The cover (being poorly designed by VW) cracks and during rain the rain runs off the window and soaks the cabin filter. The water from the soaked filter then drips down into the blower motor and shorts out the resistor module at the bottom of the blower motor. The blower will continue to operate at full speed because it is operating on an open circuit without need for resistance for the resistor pack. There is a small access "panel" at the bottom of the blower motor you will need to remove in order to see the problem, you should see a frighteningly burned looking module in there. Good Luck! Hope this helps!

Did you check all fuses after replacing everything? If you did not disconnect battery while replacement you may have blown fuse.
Good luck.

Are you sure it's the switch itself that's gone bad? Does it work on certain speeds and not others? It's more common for the resistor pack which controls your fan speeds to go bad. It's located under the glovebox.

blower motor or resistor or the blower motor control switch.