This weekend I tackled a problem I’d put off addressing for some time. The cruise control had stopped working on my 1999 BMW M3 a few months ago, but it’s a feature I rarely use. The car doesn’t go on long trips, so this wasn’t an urgent DIY project.
On the other hand, I want everything to work in my cars — you don’t want to become the kind of BMW owner that lets things go unrepaired. So I did some research on the cruise control system and possible points of failure.
I ruled out a break in the cable with a visual inspection of the engine bay. There was no way to know for sure, but I zeroed in on the clutch switch, number 12 in the Realoem diagram below:
These switches tend to fail and happily it was also the cheapest replacement possibility. BMW wanted $80 for the replacement switch, but I found it for around $10 from various online sources. Had the problem been the cruise actuator or even worse the control module itself, the price would have been much higher.
Replacement of the switch is straightforward to describe but a real PITA to do. Getting access is the easy part – simply remove the footwell cover directly below the steering column, being careful to disconnect a light and the climate control sensor. You just remove two screws and take care not to jerk it out and break any plastic tabs.
The problem comes from removing the old switch, and replacing it with the new one. The cruise clutch switch is right next to the brake circuit switch, which was such a hassle to replace a couple of years ago. Just like that switch, this one was very difficult to remove from its metal bracket.
Then when I finally did get it out, the new one was extremely difficult to snap into place. It’s possible that I made things harder for myself by going with an aftermarket part, since I did notice some very subtle differences in the plastic ridges at the front of the switch. That’s a guess, not a statement — I’m just sharing my experience. I’m not saying that if you pay 8x times the price for the OE switch it will snap right in.
After some sweating and cursing I got the old one out and the new one snapped into place. Took me almost an hour all told. I was encouraged to see some discoloration inside the old switch, indicating that it probably was the cause of the malfunction. So then all I needed to do was reinstall the footwell panel and go for a test drive.
Success – cruise control was back on line. I didn’t find as much information as I expected to in the forums on this problem, so I hope this post is useful for other owners.