Tools You'll Need:
* Socket set (various sizes, likely including 7mm, 8mm, and possibly 10mm)
* Screwdrivers (Phillips and possibly flathead)
* Pliers (needle-nose can be helpful)
* New blower motor resistor (ensure you get the correct part number for your Grand Prix)
* Possibly a flashlight
Steps:
1. Disconnect the Battery: This is crucial for safety. Disconnect the negative (-) terminal first.
2. Access the Blower Motor Resistor: The location varies slightly depending on the year and trim level, but it's typically found behind the glove compartment.
* Glove Compartment Removal: You'll likely need to remove the glove compartment. This usually involves removing a few screws (check your manual for precise locations) holding it in place. Some models might have clips as well. Carefully lower the glove compartment.
3. Locate the Resistor: Once the glove compartment is out of the way, you should see the blower motor resistor. It's usually a small, rectangular black box with wires connected to it. It might be fastened with screws or simply held in place by clips.
4. Disconnect the Wiring Harness: Carefully unplug the electrical connector from the resistor. Take note of how the connector is oriented before disconnecting it to make reconnection easier.
5. Remove the Resistor: Remove the screws or clips holding the resistor in place and carefully remove it.
6. Install the New Resistor: Install the new blower motor resistor, making sure it's properly seated. Secure it with the screws or clips.
7. Reconnect the Wiring Harness: Carefully plug the electrical connector back into the new resistor, ensuring it's securely connected.
8. Reinstall the Glove Compartment: Carefully put the glove compartment back in its place and secure it with the screws.
9. Reconnect the Battery: Reconnect the battery's negative (-) terminal.
10. Test the Blower Motor: Turn on your vehicle's ignition and test the blower motor on all speeds. If it works correctly on all speeds, you've successfully replaced the resistor. If not, double-check all connections.
Important Considerations:
* Part Number: Ensure you're purchasing the correct blower motor resistor for your 1999 Pontiac Grand Prix GT. Use your VIN or the part number from your old resistor to ensure compatibility.
* Safety: Always disconnect the battery before working on any electrical components.
* Pictures: Take pictures of the process before disconnecting anything. This can be invaluable if you get stuck.
* Repair Manual: A factory service manual or a reputable online repair guide specific to your vehicle year and model will be incredibly helpful.
If you're not comfortable performing this repair yourself, it's best to take your vehicle to a qualified mechanic. This is a relatively simple repair, but incorrect installation could damage other components.
