Auxiliary Fan Problem Need Help

[juan525i]

92 525i aux fan not working when ac is on, what can it be maybe a relay or the resistor cause fuses are ok, help me out

[gale]

Most of the time it's the ballast resistor. Sometimes the magnets inside the motor case come loose & jam it from rotating, reach in & see if you can give it a spin manually. If if spins freely, then try jumpering the hi/lo switch on side of the radiator:

http://www.nmia.com/~dgnrg/page_20.htm