To troubleshoot the blower motor, begin by checking the fuse, connections, and battery. Test for power at the motor with a voltmeter, moving the blower switch through each position. Check the thermal limiter relay assembly for damage and continuity. If the motor operates at only one speed, check for voltage issues and replace it if necessary; if there's no voltage, inspect the resistor block connector, wiring, and relays. If it doesn't operate at any speed, repeat the fuse check and test for voltage. Inspect the wiring between the fuse panel and the motor. If it works, check for bad ground at the switch and replace if needed. To replace, remove the control assembly and the screw holding the switch.