Defective Blower Motor Resistor Pack.
I have 1998 it is your door jam switchs
The blower motor speed resistor is probably burned out.
Four basic causes I have seen:Blown fuseBad blower motorBad control system, many different types.something jammed or wedged in the motor, grain from mice, sticks leaves etc.
Time for an IGNITION switch
If you are referring to the blower motor speed control, and you only have one speed, then the blower motor resistor pack is defective and must be replaced.
Check the resistance on the blower motor.
Blower speed resister is burned out.
Common causes, blower motor resistor, blower motor, wiring or controls
the blower fan resistor has gone bad.
that usually indicates a vacuum leak which causes the system to go into default mode, which is defrost.
the air wont run if engine is shut off. u need engine running to operate the compressor. i would check the rear air blower. sounds like the blower switch is not working or there is a short in blower motor get it checked before it causes a fire in vehicle . try removing rear blower fuse and see it that stops it it is a good place to start looking for the problem
If the blower runs on high it will get hot. If the blower is wearing out this will cause it to get to hot and blow.