Modifying the Boxster OBC

Activating the On-Board Computer

Thanks to Yoseif Whiteman for his technical skills and perseverance in deciphering how to do this modification, and for allowing us to post it here.

This is a great, inexpensive modification for the 2001 and earlier Boxsters.  I did it to my 2001, and it worked exactly as described.  To make the connections, I used the VW part, which consists of a wire with two Molex connectors.  You will need two of these.

0. Background

The On-Board Computer is an option that gives you these values: Temperature, Distance To Empty, Avg. MPH, and Avg. MPG. To control it, an extra stalk is added to the steering column. Up through 2000, this was a separate option. For 2001, it was bundled into the Sport Touring Package. Also, the OBC had it's own display up through 2000, but for 2001 shares the trip mileage display.

The OBC can be added afterwards by installing the stalk (or just a bipolar rocker switch) and having the dealer enable OBC in the cars computer. On pre-2001 cars, many people just enabled the OBC without installing a stalk or switch. This brought up the temp display, though they couldn't cycle to any of the other functions. For 2001, this is no longer an option.

These instructions will show you how to enable the OBC with a footwell lighting switch. You could use any switch you want, or even install the whole stalk. Installation of the stalk requires removing the steering wheel.

If you already have the OBC or PCM options, then this hack won't do anything for you.

This is not a simple hack, so make sure you know what you're doing.

This worked for me on a 2001. This information comes with no guarantees. Use at your own risk.

1. Tools & Supplies

Tools:

• T20 Torx Driver
• 10mm Socket and Driver
• Butter Knife
• Wire Cutter
• Wire Crimper
• Small Screwdriver
• Radio Code Card
• Optional: Soldering iron
• Optional: Ohm Meter

Supplies

• Molex connecters (Digi-Key http://www.digikey.com # WM2511-ND) You need two but I recommend you get a few extra. Note that these aren't a perfect fit. Apparently there is a VW part (#000.979.010) that is a wire with two Molex connecters.
• 22 Gauge wire  
• 3 Female Quick Disconnects (Radio Shack #64-4040 or #64-3131 or PAG #999.650.103.12)
• 1 Spade Terminal (Radio Shack #64-3125)
• Footwell Rocker Switch (996.613.980.00 $28.55) or any other switch. I chose this switch because it's the most non-descript.

2. Prep Work

1. Have your dealer enable OBC. They do this using the Porsche System Tool 2 (PST2). Your salesman may have no idea about this, but the service techs will. They may say, "This doesn't work anymore for 2001". Be insistent. They may charge you a small fee.
   
2. Cut three pieces of wire about three feet long.
3. Crimp Female Quick Disconnects to one end of all three wires.
4. Crimp a Spade Terminal to the other end of one wire.
   
5. Crimp a Molex connecter to the other end of the other two wires.
6. Optional: Add a drop of solder to the Molex connecters to make sure they stay in place.
7. Optional: Use the Ohm Meter to test the wires.
8. Disconnect the battery.
1. Lower the windows, lower the top, open the front trunk.
2. Remove the key from the ignition.
3. Remove the battery cover by twisting the screws 90 degrees.
   
4. Use the 10mm socket to disconnect the negative terminal.
   

3. Remove Instrument Cluster

1. Pry out the microphone cover with a small screwdriver.
   
2. Pry out the hazard button (this is easier if you turn the hazards on first).
3. Using the Torx driver remove one screw from each opening.
   
4. Lay a rag on your steering column to protect it.
5. Lift up the instrument cluster. There are clips holding it in place. Just lift firmly and they will pop out.
6. Underneith you will find three colored connecters (Grey-Blue-Green for 2001-, Black-White-Blue for 1997-2000). Disconnect these by pushing back the black cam.
   
7. The Instrument Cluster will still be connected by one harness on the right. Twist the cluster and lay it on it's face on the dashboard.
   

4. Install Switch

1. Pry off the switch panel using the butter knife
   
2. Remove the fake button (pry it out from behind)
3. Pop in the new button
   

5. Wiring

1. Open the Grey (2001-) or White (1997-2000) connecter and slide out the black terminal.
1. Open wire wrap
2. Pull back retaining lever and...
3. Simultaneously push terminal through hole in back of grey connecter
   
2. Connect the Mode Up wire by putting a Molex connecter in Slot 22 (2001-) or Slot 21 (1997-2000).  Note—Be careful when installing these connectors that they are oriented correctly—there is a notch in one side of the connector that must line up with the groove in the outside edge of the black connector, so that the connector can slide back into its cover.
   
3. Run the wire through the dashboard to pin 1 of the new switch.
4. Connect the Reset wire by putting a Molex connecter in Slot 24 (2001-) or Slot 25 (1997-2000).
5. Run the wire through the dashboard to pin 2 of the new switch.
6. Connect the third wire to the pin 4 on the switch.
   
7. Connect the wire to ground. Use the 10mm socket to loosen the ground nut and slide the spade connecter behind it.
   
8. Optional: If you want, you can also wire up the Mode down, Slot 23 (2001-) or Slot 20 (1997-2000) and Speed Gong, Slot 21 (2001-) or Slot 22 (1997-2000),

6. Put It Back Together

1. Put the Grey (2001-) or White (1997-2000) connecter back together.
2. Plug the three colored connecters back into the instrument cluster. It helps if you push the cam back and then insert the connecter. Then pull the cam forward to lock the connecter in place.
3. Replace the cluster.
4. Replace the Torx screws behind the microphone cover and the hazard light switch.
5. Replace the microphone cover and the hazard light switch.
6. Replace the switch panel.
7. Reconnect the battery.
8. Turn on the ignition.
9. Enter your radio code.

7. Troubleshooting

1. If it doesn't work, first check all of your connections.
2. Make sure you got the right slots in the Molex terminal.
3. Take it back to the dealer to check that the OBC was actually enabled.
4. If some of your instruments no longer work, make sure the three plugs are firmly seated in the back of the instrument cluster.