* Power Distribution Center (PDC) or Fuse Block: Even though you've checked the fuses, the PDC itself could be faulty. A short circuit or internal damage within the PDC could be interrupting power to both circuits without blowing a fuse. This is a very common problem. Inspect the PDC carefully for any signs of burning, corrosion, or loose connections.
* Wiring Harness: A damaged or corroded wire in the main harness supplying power to both the windows and the blower motor is a strong possibility. Look for broken, frayed, or corroded wires, especially near the PDC and where the harness might rub against other components.
* Ignition Switch: A failing ignition switch can sometimes cause intermittent or complete power loss to accessories, including power windows and blower motors. This is less likely, but possible.
* Body Control Module (BCM): Some vehicles of this era use a BCM to control various electrical functions. A faulty BCM could be cutting power to both circuits. This is more difficult to diagnose and likely requires a professional scan tool.
* Grounding Issues: A poor ground connection for either the windows or the blower motor (or both sharing a common ground) could cause this type of failure. Clean all ground connections related to the power windows and blower motor.
Troubleshooting Steps:
1. Thoroughly Inspect the PDC/Fuse Block: This should be your first step. Look for any signs of damage and carefully check all the connections.
2. Check Wiring Harnesses: Trace the wiring harnesses for both the power windows and the blower motor, looking for any damage. Pay close attention to areas where the harnesses bend or rub against other components.
3. Test for Power at the Switches and Motors: Using a multimeter, check for power at the power window switches and the blower motor connector. You should have power with the ignition on. If there's no power, the problem lies upstream.
4. Check Ground Connections: Clean and inspect all ground connections related to both systems. Make sure they are tight and free from corrosion.
5. Consider a Professional Diagnosis: If you're not comfortable working with vehicle electrical systems, a qualified mechanic with diagnostic equipment is your best bet. They can quickly pinpoint the problem using a scan tool and other diagnostic techniques.
Ignoring the problem could lead to further damage or create a safety hazard. Addressing this issue promptly is recommended.
