Stereo – Head Unit and Speaker Replacement Guide

Overview

This guide is tailored for replacing the stereo head unit and speakers in the Porsche 944, equipped with a 16v engine (1989-1991 models). Upgrading the audio system enhances sound quality and modernizes your driving experience. The 16v engine variants feature a standard 4-speaker system with a front-to-rear fader, and this procedure addresses its unique electrical and fitment details.

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Tools Required

• Phillips screwdriver
• Flathead screwdriver
• 10mm (3/8 inch) wrench
• Small hammer (for adjusting door panel speaker openings)
• Wire strippers
• Electrical tape

Parts Required

• Standard DIN head unit (with mounting frame if not factory)
• 4×6 Euro or American cut speakers (front and rear, specific models listed in steps)
• Optional: Blank switch cover (if removing fader), Porsche part 944 552 401 00

Step-by-Step Procedure

Step 1: Remove the Factory Head Unit

1. Turn off the ignition and disconnect the negative battery terminal using a 10mm (3/8 inch) wrench to ensure safety.
2. Remove the screws securing the factory head unit to the dashboard with a Phillips screwdriver. For the S2, these are typically located around the unit’s perimeter.
3. Gently pull the head unit out to access the wiring harness and antenna lead.
4. Disconnect the harness and note the two red wires with white stripes (powering the windshield antenna amplifier) that converge into a single black lead.

Step 2: Install the New Head Unit

5. Attach the mounting frame to your new DIN head unit if it doesn’t fit directly into YOUR 944’s dash slot (included with most new units).
6. Connect the new head unit’s wiring harness to the 944’s harness, matching colors or following the head unit’s manual.
7. Power the antenna amplifier by connecting a lead from the new head unit to the single black lead or the two red wires with white stripes identified earlier.
8. For the 944’s 4-speaker system with a center console fader:

For a 2-channel head unit, connect the left and right outputs to the fader’s input leads.
For a 4-channel head unit, bypass the fader by connecting directly to the four speaker leads exiting the fader, maximizing head unit control.

9. Slide the head unit into the dash and secure it with the original screws using a Phillips screwdriver.
10. If bypassing the fader, leave it in place or remove it and install a blank switch cover (944 552 401 00).

Step 3: Replace the Front Speakers

11. Remove the door panel by unscrewing the Phillips screws along its edges and lifting it off carefully.
12. Unscrew the factory 4×6 front speaker from the door with a Phillips screwdriver and disconnect its wiring.
13. Select a 4×6 speaker suited for your 944 (e.g., Alpine SXE-4625S fits perfectly). For American cut speakers, loosen the door panel bottom with a flathead screwdriver to fit the mounting plate.
14. Verify depth: The door window channel limits clearance. Reuse the factory 1/4 inch (6mm) spacer for up to 1-3/4 inch (44mm) depth. Deeper speakers need a thicker spacer, but factory grills won’t fit flush.
15. If the speaker frame doesn’t sit flush, tap the door panel’s speaker opening with a small hammer to slightly widen it.
16. Connect the new speaker’s wiring, secure it with the original screws, and attach the factory grill (ensure no protrusions exceed 1/4 inch (6mm) above the speaker).
17. Reattach the door panel and tighten the screws.

Step 4: Replace the Rear Speakers

18. Access the rear speakers in the 944’s cargo area by removing the trim panels with a Phillips screwdriver.
19. Unscrew the factory 4×6 rear speakers and disconnect their wiring.
20. Install a compatible 4×6 speaker (e.g., Rockford Fosgate HPC1246 fits the S2 rear perfectly). Connect the wiring and secure with the original screws.
21. Replace the trim panels and tighten the screws.

Post Procedure Checklist

• Reconnect the battery and turn on the ignition to test the head unit and all four speakers.
• Confirm sound from each speaker; adjust fader or head unit controls as needed.
• Ensure the head unit powers on and the antenna amplifier works (test radio reception).
• Check door panels and rear trim for secure fitment with no rattles.

Sources

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