Cruise Control

[murphrt]

The cruise control on my '95 525i (automatic) will not engage.

Where do I start ?

[632 Regal]

Check fuses?

[shogun]

Brake light switch must be correct installed + working. The brake light switch is important, if the contact are always on 'brake', cruise control will not engage.The brake light switch also has a brake light test switch
https://www.bmwtechinfo.com/repair/m...es/7411209.jpg
from here https://www.bmwtechinfo.com/repair/main/741en/index.htm
wiring diagrams and electric troubleshooting manual here http://shark.armchair.mb.ca/~dave/BMW/e34/

[Jehu]

Here is a lot of information about the module if it comes to you wanting to open it and inspect it

This is a cached page there should be a link to the PDF file at the top when it opens that will download it with all the images which are not hosted on this cache..
http://webcache.googleusercontent.co...&ct=clnk&gl=us

[shogun]

Here is the same, but Timm has it complete with the pics http://www.meeknet.co.uk/e32/BMWCrui...hnicalData.pdf
and here in Japan alpinakozou.web.fc2.com/image/pdf/cruise-control.pdf
and much more here http://bigcoupe.com/phpBB2/viewtopic.php?t=23155

[Clarksonvalley]

You might also check the cable from the cruise control unit to the throttle body - I had my cable fray, get stuck in the cable sheath and hold the throttle body open. Perhaps your cable is broken.

Tom
1995 540i

[nk530]

Bump for another great and extremely helpful post. Just rebuilt the module in my 540. The shaft was so corroded that neither the drive gear nor the winding gear could turn at all. Cleaned up the shaft with a dremmel, now it's fine.

Be careful that you don't over-wind the clock spring. I had it so installed so that the cruise control cable would keep the throttle plate from closing.

Had it to rip it out 3 times to get it right cuz I'm an idiot.

It's still not working right, so I might have to do it a 4th time. I think I may have wound the ribbon backwards. It surges when I set the cruise. I guess I should pay more attention when I'm taking things apart.

[Jehu]

Bump for another great and extremely helpful post. Just rebuilt the module in my 540. The shaft was so corroded that neither the drive gear nor the winding gear could turn at all. Cleaned up the shaft with a dremmel, now it's fine.

Be careful that you don't over-wind the clock spring. I had it so installed so that the cruise control cable would keep the throttle plate from closing.

Had it to rip it out 3 times to get it right cuz I'm an idiot.

It's still not working right, so I might have to do it a 4th time. I think I may have wound the ribbon backwards. It surges when I set the cruise. I guess I should pay more attention when I'm taking things apart.

If your problem is the cable is not allowing the throttle plate to rest check the orientation of the CLEVIS inside the end of the cable connector.. it can appear to be seated but it needs to be fed through a slot to seat properly and allow the throttle to relax.

I discovered this when changing my cable. The first attempt the cable seemed too short. Then I searched and found a thread where the clevis orientation was mentioned . I checked it , fed it in through the slot and it was now the right length and the throttle plate sat properly.

[nk530]

Success! I got it working finally. It was just as I suspected. I wound the belt the wrong way around the drum.
I think what confused me was that in the document it says the spring takes up slack in the cable. This isn't actually the case. The spring just forces the drum back to its home position. If you set it up so the spring takes up slack in the cable, you risk the tension in the spring + the drag in the cable overwhelming the spring on the throttle plate. If this happens, the throttle won't close and you get taken for a ride.