1990 Buick Lesabre Heater Fan Motor Blower

The blower motor resistor is located on the evaporator case

Thanks for the info. I have so far replaced the blower motor resistor, the blower motor itself. The blower still will only run on the high speed setting. It will not run on the other speed settings. Any ideas on what I can check next to resolve this problem?

Test the AC and heater blower switch

I tested the AC and heater blower switch. Replaced both switches, Same results. The fan speed will only operate at the high setting. I did notice that when the fan speed switch is cycled from the low to the high setting, the LED for the radio which indicates the radio station that you are turned into flashes and goes out. Are there any other areas that I can check?

See below Check the blower motor resistor every wire should have power as you switch the fan position. If no power recheck the AC/Heater switch

There are (4) wires on the resistor electrical plug, Dark Blue, Light Blue, Beige, and Brown.

With the blower speed set at low, There was No power at the Dark Blue, Light Blue, or Beige wire. There was power at the Brown wire.

With the blower speed set at medium, There was No power at the Dark Blue or Light Blue wire. There was power at the Beige and Brown wire.

With the blower speed set at medium high, There was No power at the Dark Blue wire. There was power at the Light Blue, Beige and Brown wire

With the blower speed set at high, There was No power at the Dark Blue or Beige wire. There was power at the Light Blue and Brown wire. Are there any other areas that I need to check? Thanks for any info you can give!