* Blower Motor Resistor: This is the most frequent cause of a malfunctioning blower motor in Cadillacs of that era. The resistor controls the fan speeds. If it fails, you might get no fan at all, or only one speed.
* Blower Motor Itself: The motor could have simply worn out or burned out.
* Wiring Issues: A break or short in the wiring to the blower motor is another possibility.
* Relay: A faulty relay could also prevent the motor from receiving power.
* Fuse (Less Likely, but Possible): A blown fuse is possible, but usually results in a complete lack of function across all fan speeds.
Before replacing anything:
1. Check the fuses: Consult your owner's manual to locate the fuse(s) related to the blower motor. Visually inspect them for blown elements (a broken wire inside the fuse).
2. Check the fuse box carefully: Sometimes a fuse may look intact but still be bad. Use a multimeter to test it for continuity. Make sure to disconnect power to the fuse box before testing!
3. Listen near the blower: Turn on the fan to its highest setting. You might be able to hear a clicking or grinding sound indicating a problem with the blower motor itself.
If the fuses are okay, the problem is almost certainly *not* a simple blown fuse and you'll need to investigate those other components (resistor, motor, wiring). It's generally recommended to take it to a qualified mechanic, especially if you're not comfortable working on car electrical systems. The blower motor and resistor are often difficult to access.
