For a basic circuit check of the blower motor system, begin by inspecting the fuse and all circuit connections for looseness or corrosion, ensuring the battery is fully charged. Back probe the blower motor connector with two large straight pins while leaving the connector plugged in, then connect a voltmeter across the two pins. With the transmission in Park and the parking brake applied, turn the ignition switch to the On position (engine not running). Have an assistant cycle the blower switch through each position while noting the voltage readings, looking for changes in voltage to confirm that the blower switch can vary the motor speed at different positions. If voltage is present at the connector but the motor doesn't operate, test the motor separately by disconnecting the connector and connecting one terminal to a good ground and the other to the battery positive terminal through a fused jumper. The motor should run at its highest speed; if not, check connectors and wires. If the motor still doesn't run, it may be faulty. To check the blower motor resistor assembly, locate it on the heater case to the right of the blower motor, and visually inspect it for damage. Check the resistor block for continuity between all terminals and replace the thermal limiter circuit if it's been opened due to excessive heat.For a blower switch check, turn the ignition switch Off, disconnect the blower resistor electrical connector, and use an ohmmeter to check for continuity to ground at each wire terminal with the blower switch in its corresponding position, making sure the ignition switch is Off before probing the Hi-speed circuit. An open circuit in any position suggests a defective switch or an open wiring harness. Remove the control panel to check the switch for continuity, and if all switch positions show no continuity, verify continuity in the ground circuit.For blower motor replacement, disconnect the negative battery cable and, on 2001 and later models, move the cruise control servo aside by disconnecting its electrical connector and removing the mounting screw. Disconnect the blower motor connector and remove the vent tube if present. Then, remove the blower motor mounting screws, the blower motor wheel hub push nut, and the clamp from the shaft, and pull the blower motor wheel from the shaft. Installation is the reverse of these steps.
