The air-cooled Porsche 911 had power windows starting back in 1974. Many of these cars can have window switch issues due to wiring problems with aftermarket alarms, audio modifications, or simply due to old age. Fortunately they are fairly straightforward to replace. Read on to find out how.
Porsche model years applicable:
Tools needed to replace power window switches on an air-cooled Porsche 911:
- Trim panel removal tool
- Screwdriver set
- Hex wrench set
- Multimeter or automotive test light
- Needle nose pliers
- Circlip pliers
- Label maker or masking tape and permanent marker (optional)
- Lithium grease (window mechanism lube)
Parts needed to replace power window switches on an air-cooled Porsche 911:
- 1-3 window switches (all 3 are the same part number)
- 1 mirror adjuster switch (if yours is broken)
- Service manual for your car’s model year (with wiring diagrams)
Steps to replace power window switches on an air-cooled Porsche 911:
Warning: Do not perform this procedure if you cannot read automotive wiring diagrams or are not comfortable with basic automotive electrical work. You may discover wiring damage or modifications that you will need to repair at that moment using the factory wiring diagrams as a reference.
Step 1: Disconnect Negative Battery Terminal
Disconnect the negative battery terminal before starting.
Step 2: Pry Window Switch Out
First we will attempt the quick method. Using a plastic trim tool you can pry behind the plastic rectangular switch bezel and pop the switch out of the door card hole. Be careful not to pry up on the metal rectangular bezel that is attached to the door card directly behind the switch.
As soon as it is free, very carefully pull back the rubber boot over the back of the switch body and grab onto the individual spade wire terminals behind each switch. The switch harness wires are very short and they may become disconnected as you pull out each switch.
Theoretically you should now be able to disconnect each terminal behind each switch, hold on to them, and using the colors of the wires reconnect a new switch. If you can do this, by all means take the shorter route. Step 4 below shows the connections for each individual switch.
More than likely though, the harness will be too short, or the wire colors will be difficult to identify due to darkening of the insulation due to age or heat, or a wiring issue in the door will prevent window function. If this is the case you will need to disassemble the door card to get to the remainder of the switch harness inside the door. This is a few more steps but still pretty easy to do.
Step 3: Disassemble Door Card
First remove the door card top trim at the base of the window. There is a screw at the front end and a small cap at the rear covering another screw.
If you have power mirrors, spin off the threaded round bezel around the power mirror adjuster. A pair of circlip pliers insert perfectly in the two bezel holes)
The top trim should now lift off the top edge of the door card. Leave the mirror adjuster hanging on its wire harness. If the mirror adjuster switch threaded collar is broken off the switch body, replace it with a new one.
Next carefully pry off the center cap off the door lock knob, loosen the screw, and remove the knob assembly from the door card.
Next remove the door pocket and door pocket lid. The lid has 3 screws inside the pocket at the rear that hold the rubber hinge assembly to the door card and pocket. Remove these and the lid lifts off.
There are several more screws around the outer perimeter of the door pocket. Once you remove these you can remove the pocket from the door card itself.
Now remove the door handle and release lever assembly. If you look from the front of the release lever, you will see a release lever rod. Lift up on the end of the rod and unhook it from the lever.
Now the lever can be rotated out further exposing the door handle two lower mounting screws.
Remove those two and the upper two to completely release the door handle.
Using a trim panel tool, gently pull up and release each door card fastener all the way around to remove the door card itself from the steel door. Be very careful as window switch wires are very short and may be speaker wiring still connected to speakers on the door card.
There should be a plastic vapor barrier on the steel door to protect the door card from moisture. If it is not there you will need to buy one or make one out of plastic sheet and install it before mounting the door card back on.
Step 4: Disconnect Switch & Identify Wires
Disconnect the 5 individual terminals behind each switch you will be replacing. Identify each connection based on the switch, the terminal locations 1-5 behind each switch, and the colors of the wires. Each of the three switches (two on the driver door and one on the passenger door) is the same switch part number. However they do have unique wiring arrangements shown below. The original switches have tiny numbers next to each switch terminal but just in case they are not present, you can identify them by using the sixth unused terminal to indicate off of. As in all German cars, the first color indicates the color of the wire and the second color indicates a stripe color (if it is present). Each connection is a single wire unless it is specified to be two wires.
Note: the wire colors change over the years so consult your service manual wiring diagrams for the correct colors for your year. The ones listed below are for a 911SC.
The colors of the wires may have faded over time, so look further down the harness to help identify colors and use process of elimination as needed to reconnect the wires. If it helps use a label maker or masking tape and a marker to make wire ID tags behind each terminal.
Step 5: Connect New Switches & Test
Reconnect the new switch or switches on the terminals and reconnect the negative battery terminal to test it while the wiring is accessible. Disconnect the battery terminal after testing and before working on any wiring. Connect the switches with the wiring fed through the door card so that when you reassemble the door card you don’t have to disconnect/reconnect switch wiring again.
Due to the way the circuit is laid out, the passenger door window switch may not work if the driver door passenger window switch is bad or wired incorrectly. Consult your service manual wiring diagrams for further detail on the switch circuit.
If there are any wiring issues you may encounter them at this time. Leftover audio or aftermarket alarm wiring can show up spliced into random areas in the doors. If you see something that doesn't look factory, you may need to reference the wiring diagrams in your service manual to identify and fix any problematic connections.
Lastly, while you are in the door interior, this is a good time to re-grease the power window regulator.
Step 6: Reassemble Door Card & Switches
If you were able to replace a switch without door card removal and it works correctly, simply press it back into the door card hole and you are done. If you had to disassemble the door card, at this time reassemble it in the reverse order of the disassembly shown in Step 3. Start with leaving the switches loose in the door card holes and stick the vapor barrier back on the metal door. Then press the door card perimeter fasteners back onto the metal door.
Before reassembling the rest of the door, press the switches back into the door and reconnect the negative battery terminal. Test the switches one last time in their final installed position. If they are ok then continue to reassemble the door handle, door lock knob, top door trim, and door pocket and lid back on the door card.
If needed, repeat the entire process on the passenger side door to replace that switch.
Your power window switches are now fully operational once again. Enjoy windows down driving and listen to that flat six sing. If you have any questions or comments about this process, leave them in the comments section below.
Having explored the fields of aerospace, power generation, automotive aftermarket, and concept car engineering, I'm now a development engineer for Mazda North America. In my spare time, you can find me wrenching on anything, but mainly cars of the air-cooled variety. @joe_engineer