cruise control troubleshooting

[shadowpuck]

hi everyone....

just wanted to get some input here....

our '93 525i has been running great, no issues.

i've been driving it on my daily commute, which is 120 miles round trip.

given that drive, i use the cruise control almost constantly.
today, while driving along at about 70mph, the cruise control just stopped.
it disengaged and hasn't worked since. it doesn't act like it wants to engage.

so, any troubleshooting i can do? can i put a meter on anything?

i've not had any problems with the brake light switch - no weird messages about brake light circuits or the like. the instrument cluster/speedo, etc. all works fine, reads correctly and doesn't act like its having a problem.

i haven't noticed any transmission issues, the gear indicator (automatic) seems to show the right gear, etc.

just wondering where i can go on this one. my brake lights are working fine.

based on my research, looks like there's a few areas to check:
speed sensor
brake light switch
transmission range switch
cable
actuator

before i start digging into everything, just wondered if anyone had encountered this scenario and if so, how was it fixed?

thanks!!

[shogun]

this might help
http://www.bavtech.com/bmw-technical-downloads/index.php

[pingu]

I think I had the same problem a year to two ago.

Shogun has posted a useful link that shows how the cruise control module can be disassembled. That link didn't address the electrical problem that I was having.

In my case, I seem to recall that there was an electrical problem that stopped the electric motor (inside the cruise control actuator) from being properly connected.

If you search my posts for a year or two back, together with keywords such as "cruise" and "control", you'll see that I did a post with pictures showing how to fix the electrical connection. My memory is hazy but I think the problem was a poor connection between the motor and the electrical connector on the outside of the cruise control actuator.

Good luck!

[shadowpuck]

shogun - great link - thank you so much for posting it! i've been reading through all the documentation.

pingu - i'd love to see that post, can you give us a link or something? i did a search on your username and using just about every combination of cruise, control, and actuator but only found references saying a post had been made, but no actual post.....sorry!

[pingu]

Hi there, I definitely made the post. I've re-attached one of the photos from my original post. That post must have been in 2007, probably around April or May, give or take a month or two.

You'll see from the attached photo that there are two red arrows that point to sockets on the printed circuit board (PCB) that is inside the cruise control actuator.

As far as I can remember, the sockets on the PCB are meant to connect to the cruise control actuator motor (not shown in the photo, although the photo does show a solenoid) but the sockets were so old that they no longer made a good connection. I slightly bent the two sockets so that they grasped more firmly, and thus made a better electrical connection, to the motor. I guess with time the sockets had gone a bit soft.

That's as much as I can remember so if you want to know more then you'll have to have another go at finding my original post. Good luck!

[shadowpuck]

pingu - the only way i could find your post was to search all posts by you, with no keywords....very odd....

for others; here's the thread; unfortunately, for whatever reason, i don't see any photos or a PDF (other than the PDF linked).....

http://www.bimmernut.com/forum/showthread.php?t=30371

the information is invaluable.....

[pingu]

Well found! Just as well I haven't got a gazillion posts!

Weird that a search didn't work. I think the database was changed over a few months back so maybe that's what's stopped the keyword search from working?

I've had a dig and have found the rest of the photos on my PC. I've attached them all to this post (including the one that I'd already attached to the previous post - now they're all here together).

With regard to the PDF, the only PDF is the one linked to in the previous thread (which is the same PDF that Shogun mentioned a few posts ago).

[pingu]

Weird, I can see the "attached photo" icon but no sign of the photos themselves. I'll try to attach them again...

[pingu]

Still no luck. I'll try one at a time.

[pingu]

And again...

[pingu]

And finally.