Electric Window Troubleshooting – 2.5L NA

Overview

This guide helps diagnose and fix issues with the electric windows on your Porsche 944 (8-valve engine configuration variants, 1983–1988). Problems like windows not moving or moving slowly can stem from fuses, relays, switches, wiring, or motors. This procedure identifies the cause, focusing on the pre-1985.5 (1983–1985.5) and 1985.5 onwards (1985.5–1988) variants, ensuring your windows operate smoothly. Proper troubleshooting prevents unnecessary repairs and maintains functionality.

Pink and blue text represent links to additional resources, tools, parts, and partner websites.

Tools Required

• Voltmeter/Ohmmeter (test meter)
• Trim removal tool
• Phillips head screwdriver
• Small flat-tip screwdriver (for switch removal)

Parts Required

• Fuse, 944 615 111 00 (16A for Pre-85.5, 30A for 85.5 Onwards, if blown)
• Power window switch, 477 959 855 (if faulty and not repairable)

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 for Window Movement

1. Try operating both driver’s and passenger’s windows using their respective switches.
2. If neither window moves, proceed to Step 2 to check the fuse and relay.
3. If only one window is not working, skip to Step 3 to test the switch, wiring, or motor for that side.

Step 2: Inspect the Fuse and Relay

4. Locate and check the power window fuse, as a blown fuse prevents both windows from moving:

For Pre-85.5 models:

• Check Fuse 8 (16A) in the Additional Fuse Panel, located near the dashboard. Remove the fuse and inspect for a broken filament. Replace with a new fuse, 944 615 111 00, if blown.

For 85.5 Onwards models:

• Check Fuse 4 (30A) in the Central Electric Panel, located in the passenger footwell. Remove the fuse and inspect for a broken filament. Replace with a new fuse, 944 615 111 00, if blown.

5. If the fuse is good, test the power window relay, as a faulty relay also stops both windows:

For Pre-85.5 models:

• Locate the relay on the lower left side of the center console near the DME computer. Remove the relay and jumper terminals 30 and 87 with a wire to bypass it. Test window operation without turning on the ignition.

For 85.5 Onwards models:

• Locate the relay on the Central Electric Panel (position G7). Remove the relay and jumper terminals 30 and 87 with a wire to bypass it. Test window operation without turning on the ignition.

6. If windows work after jumping the relay, replace the relay. If not, proceed to Step 3 for switch or motor issues.

Step 3: Test the Window Switch and Wiring

7. If only one window is faulty, the issue is likely the switch, wiring, or motor. Start by testing the switch.
8. Remove the faulty window’s switch from the door panel:

• Use a trim removal tool or small flat-tip screwdriver to carefully release the four tabs (two on top, two on bottom) holding the switch. Avoid breaking the tabs.

• For the passenger window, test both the driver’s side passenger switch and the passenger door switch, as they are wired in series.

9. Turn the ignition to the ON position.
10. Use a voltmeter to check for approximately 12 volts DC at the switch plug:

• Measure between terminal 4 (red/green wire) and ground.

• Measure between terminal 5 (red/blue wire) and ground.

• If 12 volts is present, the power supply and wiring to the switch are good. Proceed to test the switch.

11. Use an ohmmeter to test the switch:

• Press the switch in the “open” direction. Check for low resistance (less than 1 ohm) between terminals 1 to 4 and terminals 2 to 3.

• Press the switch in the “close” direction. Check for low resistance between terminals 1 to 3 and terminals 2 to 5.

12. If resistance is high or infinite, the switch is faulty. Proceed to Step 4 to repair or replace it.
13. If the switch tests good, swap it with a known good switch (e.g., from the driver’s side if working) and test the window. If the window works, the original switch is faulty. If not, proceed to Step 5 to check the motor.

Step 4: Repair or Replace the Window Switch

14. If the switch is faulty, try cleaning it before replacing:

• With the switch removed, face the back of the switch up to prevent internals from falling out.

• Insert a small flat-tip screwdriver into the side of the terminal block to release the four tabs (two on each side) holding it to the switch body. Remove the terminal block.

• Carefully remove the switch internals and inspect the contacts. Dirty contacts often cause high resistance.

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

• Reassemble the switch, ensuring smooth operation.

15. Test the cleaned switch using the ohmmeter as in Step 3 (instructions 12–13). If it passes, reinstall and test the window.
16. If the switch still fails or operates poorly, replace it with a new switch, 477 959 855.

Step 5: Check for Slow Window Movement

17. If the window moves slowly, the issue may be a dragging mechanism or a weak motor.
18. Lubricate the window mechanism tracks:

• Follow this link to ensure this step – Door Panels – Removal and Installation – of the process is followed accurately to access the window mechanism.

• Apply silicone-based lubricant to the window tracks and guides. Operate the window several times to distribute the lubricant.

19. Test window speed. If still slow, check the motor voltage:

• Follow this link to ensure this step – Door Panels – Removal and Installation – of the process is followed accurately to access the motor plug.

• With the ignition ON, press the window switch and measure voltage at the motor plug. It should be approximately 12 volts.

• If voltage is low, check wiring for corrosion or loose connections. If voltage is correct but the window is slow, the motor may be failing and should be replaced.

Post Procedure Checklist

• Verify both windows move smoothly in both directions.
• Check that all switches operate without sticking.
• Ensure no loose wiring or components inside the door panel.
• Confirm the fuse and relay (if replaced) are secure.

Sources

• Clark’s Garage
• Pelican Parts
• Porsche 944 Workshop Manuals
• YouTube