This is one of those mods that only makes sense once you’ve driven a stripped-out track car a great distance on the highway. You NEED cruise control. In your track car. Stay with me here.
This was going to be the year I finally got a trailer. But the opportunity to buy this M3 came along, so all of my money for the trailer went into this car. For now, it’s still street legal and I have to be able to drive it to the track and back. So to keep out of jail, I need cruise control. The problem is that the buttons for that were on the sport steering wheel which I replaced with Sparco wheel and quick release. I was able to salvage and adapt the clock spring so I still have a working horn button. That also means the wiring that controls the cruise control is still there.
The beauty of the design of BMWs of this era is that many parts are interchangeable. In this case, I’m going to grab a cruise control stalk off of an E85/E86 Z4. It plugs right into the clock spring housing and all you have to do is jump some wires and modify the housing.
Disconnect your battery and wait 15 minutes for the ABG module to power down (if you still have airbags.) Remove the steering wheel and the steering column housing. Remove the lower housing by pressing the center of the two pins and pry the lower half away from the top half of the column cover. Remove the screw from the top of the housing but you don’t have to remove it from the column, just slide it up to get access to the clock spring set screws.
You’ll need a suitable CC stalk (part number 61316940989) and plug 61138380696. My plug came with four wires already installed. You will need to connect three of the wires. At the bottom of the clock spring, remove the ten pin connector and look at the end of it. The pins are numbered on each row of the connector. Then look at the side of the four pin plug referenced above for the pin numbers . Connect the wire from pin 10 to pin 4 (power); pin 8 to pin 2 (cruise control); and pin 7 to pin 1 (ground).
Plug the stalk into the housing and then plug the 10 pin connector back into the clock spring. Plug the four pin connector you just wired to the stalk and reattach the clock spring housing to the steering column. Replace your steering wheel and airbag if you have one. Reconnect the battery and you’re ready to test the system.
- Pressing the steering column lever upwards (on): Cruise-control system on
- Pressing the steering column lever upwards or downwards (off): Cruise-control system off.
- Pressing the steering column button at the side (I/O): Activates resumption of cruise-control system. The vehicle accelerates or decelerates exclusively from non-controlled operation to the driving speed last set and maintains this speed.
- Pressing the steering column lever briefly backwards (+): Sets the road speed. If the cruise-control function is activated, the current vehicle speed is kept constant.
- Pressing and holding the steering column lever backwards (+): Increases the road speed. The vehicle accelerates for the period the switch is actuated up to its maximum speed.
- Pressing the steering column lever briefly forwards or holding pressed (-): Brakes the road speed. The cruise-control system is deactivated for the period the switch is actuated. However, it is not possible for the driving speed to drop below the minimum set speed.
If it all works as planned, then you just need to modify the lower column housing to fit around the new stalk. The lower cover is part of the crash protections for your knees. Inside the cover is a metal plate and some expanded polystyrene foam. After you measure and cut the outside to make room for the stalk, you’ll also need to remove a little on the bottom of the cover to make room for the mechanicals of the stalk. Measure twice and cut once.