1. Test the Switch:
* Visual Inspection: Carefully inspect the driver's side window switch for any obvious signs of damage, melting, or loose connections.
* Continuity Test (Advanced): If you have a multimeter, you can test the switch's continuity. Disconnect the switch connector. With the multimeter set to ohms, check continuity between the appropriate terminals as you actuate the switch in all positions (up, down, etc.). Lack of continuity in the correct position indicates a faulty switch. *Caution: Ensure the power to the window system is OFF before doing this test.*
2. Test the Motor:
This is more complex and may require some disassembly:
* Access the Motor: You'll need to remove the door panel to access the window motor and regulator. There are many online resources and repair manuals (e.g., Haynes, Chilton) with specific instructions for your Grand Prix model year. *Be careful not to damage the door panel's clips during removal.*
* Visual Inspection: Once you have access to the motor, inspect it for any visible damage, such as burnt wiring, melted plastic, or seized components.
* Power Test (Advanced): With the connector to the motor disconnected, use your multimeter to check the voltage at the motor's connector while operating the window switch. If you don't get voltage at the correct terminals when the switch is activated, it points to a wiring problem or a faulty switch (after you've ruled out the switch above). If you *do* get voltage, the motor is likely the culprit.
* Manual Test (Dangerous): As a last resort and only after performing the visual and voltage tests, you can try to manually operate the motor's gear using a small screwdriver (extremely carefully!) to see if it's seized. This is risky and could potentially damage the motor further if it's already faulty.
3. Check Wiring and Connectors:
While less likely given the temperature-dependent failure, inspect the wiring harness leading to the motor for any signs of wear, fraying, or corrosion, especially near the door hinge area where it experiences flexing.
Likely Culprit:
Given the scenario, a faulty window motor is the most probable cause. The resistance within the motor windings increases as it heats up, eventually preventing it from functioning. Replacing the motor is usually the solution.
Important Notes:
* Safety First: Disconnect the negative battery cable before attempting any electrical tests or disassembling anything.
* Repair Manual: A repair manual specific to your 1997 Grand Prix will be invaluable in guiding you through the disassembly and reassembly process.
* Professional Help: If you're not comfortable working on car electrical systems or don't have the tools, it's best to take your Grand Prix to a qualified mechanic.
By systematically testing these components, you can pinpoint the exact cause of your window problem. Remember to proceed carefully and prioritize safety.
