On most cars there is a high speed relay that can go bad and would need replaced .
usually the blower motor resistor pkg. located on or near the blower motor
change the blower motor resistor . this controls the speeds . thanks paul
The blower motor speed resister is burned out.
If all speeds do not work, suspect the fuse, the switch, the switch connector or the blower motor. If only high speed works, suspect the blower motor speed resistor. If low speeds work and not high, suspect the blower motor relay.
If the blower works on slower speeds only I would suspect the high speed blower motor relay (under the hood in the power distribution box) or the switch itself. The blower speed resistor is working if all the slower speeds work.
Normally when some speeds work and others don't, the problem is a bad, Blower Motor Resistor Pack. You will find it somewhere near the blower motor.
When the fan is on high it does not run through the blower motor resistor. The low speeds don't work because the blower motor resistor is bad.
If the blower motor randomly and intermittenly quits and does not work, chances are good the blower motor itself is faulty, if the blower motor does not work on all fan speeds from low through high, it most likely needs a blower motor resistor.
The common cause is a failed blower resistor.
Probably the blower motor speed resistor is partially burned out.
If you only have high speed I would blame the blower speed resister. If you have no speeds and the fuse is good, I would blame the blower motor or the switch.
If a blower motor resister is bad the fan won't work at all or will only work on certain speeds. And you will see on the resistor a missing link where it burnt out kind of like in a light bulb