Electric Window Troubleshooting

Overview

This guide helps you figure out why the electric windows in your Porsche 944 (16v engine) aren’t working properly. Whether they won’t move or move too slowly, we’ll walk you through checking the fuse, relay, switches, wiring, and window mechanism to pinpoint the issue. Fixing this yourself can save time and keep your 944’s windows running smoothly.

Tools Required

• Test meter (Voltmeter/Ohmmeter)
• Trim removal tool (if door panel removal is needed)
• Phillips head screwdriver (if door panel removal is needed)
• Small flat-tip screwdriver

Parts Required

• Fuse, 30A – 944 612 311 00 (if replacement is needed)
• Power window relay – 944 615 117 00 (if replacement is needed)
• Window switch – 944 613 621 00 (if replacement is needed)

Required Additional Procedures

Steps in these procedures are required to complete this process:

• Door Panels – Removal and Installation

Step-by-Step Procedure

Step 1: Check the Fuse

1. If neither window moves, the fuse might be blown. Since the Porsche 944 16v engine is a late-model 944 (1985.5 and newer), locate the Central Electric Panel behind the passenger-side footwell cover.
2. Find Fuse 4 (30A) in the Central Electric Panel.
3. Inspect the fuse visually or use a test meter to check for continuity. If it’s blown, replace it with a new 30A fuse (944 612 311 00).
4. Test both windows. If they still don’t move, move to the next step. If only one window fails, the fuse is fine—skip to Step 3.

Step 2: Test the Power Window Relay

5. If neither window works (and the fuse is good), the relay might be faulty. In the 944, the relay is on the Central Electric Panel, position G7.
6. Remove the relay (944 615 117 00).
7. Jumper terminals 30 and 87 on the relay socket with a wire or paperclip to bypass the relay.
8. Test the windows without turning on the ignition. If they work, replace the relay. If not, proceed to the next step.

Step 3: Troubleshoot the Window Switch and Wiring

9. If only one window fails, the issue is likely the switch, wiring, or motor. Start with the switch since it’s the most common problem.
10. Remove the suspect switch from the door panel. Use a small flat-tip screwdriver to carefully release the four tabs (two on top, two on bottom)—they’re fragile, so go slow.

11. Turn the ignition to the ON position.
12. Use a voltmeter on the switch plug to check for about 12 volts between terminal 4 (red/green wire) and ground, and terminal 5 (red/blue wire) and ground. If you get voltage, the wiring to the switch is good.

13. Use an ohmmeter to test the switch:

Press the switch to open the window—check for low resistance (less than 1 ohm) between terminals 1 and 4, and 2 and 3.

Press the switch to close the window—check for low resistance between terminals 1 and 3, and 2 and 5.

14. If the readings are off, the switch is bad. Either replace it (944 613 621 00) or clean it (see Step 5).
15. If the passenger window fails, test both the driver’s and passenger’s switches by swapping a known good switch (e.g., the driver’s) into the passenger side.

Step 4: Check for Slow Window Movement

16. If the windows move but are sluggish, the mechanism might be dragging. Follow this link to ensure this step—Door Panels – Removal and Installation—is followed accurately to access the tracks.
17. Lubricate the window tracks with a silicone-based lubricant.
18. Test the window speed after lubrication.
19. If still slow, check the motor voltage. Follow the Door Panels – Removal and Installation procedure again, then use a voltmeter at the motor plug while pressing the switch. You should see about 12 volts. If not, the motor or wiring may need repair.

Step 5: Repair a Faulty Window Switch (Optional)

20. If the switch tests bad but you’d rather fix than replace it, use a small flat-tip screwdriver to release the four tabs holding the terminal block on the back of the switch. Keep the back facing up to avoid spilling the internals.

21. Remove the terminal block and inspect the contacts. Dirty contacts are common if resistance was high during testing.

22. Clean the contacts with electrical contact cleaner or fine sandpaper until shiny.

23. Reassemble the switch and test it again per Step 3, ensuring smooth operation.

Post Procedure Checklist

• Test both windows for normal operation (up and down).
• Check that the switches feel smooth and responsive.
• Ensure no unusual noises come from the window mechanism.
• Verify the door panels (if removed) are securely reinstalled.

Sources

• Clark’s Garage
• Pelican Parts
• Porsche 944 Workshop Manual, Volume 1
• Youtube