e30 Cruise control

**DanZ3** · 09-23-2019, 10:17 AM

I have an 87 325i Convertible that is new to me. I'm just going through the car and making a list of items that need attention. One item that I am just getting into is the non-functioning cruise control. I searched and read everything I could find and will dig into it a bit more. I've checked to verify the fuse, verified power to the clutch switch and function/adjustment, verified brake light function, all three. An observation that I did see is that I can pull the end of the cable that attached to the throttle away from the connection with little to no effort. It's almost like its not connected to anything at the other end. Is this normal or could it be disconnected in the servo control? The investigation continues but thought I'd ask.

**richardodn** · 09-24-2019, 06:45 PM

Sounds like the cable is likely broken. It's replaceable separately. It should be PN 65711386243 but be sure to verify.

**DanZ3** · 09-25-2019, 11:35 AM

Thanks. That was my thought. I’m working through the entire system anyway. Started with fixing the brake warning light. Brake and clutch switches seem to work fine verified with continuity meter. All brake lights work with no faults. Next is to verify the cable integrity.

I just sold my 74tii and by comparison the electrics are a magnitude more complex.

**superj** · 09-25-2019, 01:55 PM

I bet

**DanZ3** · 10-04-2019, 06:23 PM

Update: verified that the cable wasn’t broken. Checked all connections and grounds including the connection to the speed signal at the instrument cluster. Replaced the control module with a known functioning one. The original had evidence of someone opening the aluminum box. Checked that all switches, clutch,brake and column switches were functional. Not sure where to go with this short of replacing the actuator assembly. Thoughts on anything I overlooked? Frustrating.

**superj** · 10-04-2019, 08:53 PM

No idea from me

**323i E30** · 10-05-2019, 02:46 AM

If you're new to the E30, this data collection might come in handy: https://www.e30zone.net/e30wiki/inde...itle=Main_Page
It's british, so 99% is about RHD cars. Lot's of info tough

Article about cruise control: https://www.e30zone.net/e30wiki/inde...Cruise_Control
I've never owned an E30 with cruise control, so that's all I got.

**DanZ3** · 10-05-2019, 07:32 AM

Looks like good information. A couple electrical checks that I can try.

Sent from my iPad using Tapatalk

**richardodn** · 10-05-2019, 09:41 AM

If everything else has checked out, I'd bet the problem is the speed output connection from the cluster. That's the green connector pictured. All those ports with the same shape are electrically the same. You can use any one of them.

**DanZ3** · 10-30-2019, 07:43 AM

Update: still no cruise. I did check and clean the speed sensor in the differential. Seems fine checked with a multimeter. I did notice that the computer output for speed doesn’t register anything. Speedometer works fine. Any thoughts?

**DanZ3** · 10-30-2019, 08:37 AM

Edit: just realized that the output I was looking at was for speed limit warning not real time speed. My 2013 has real time speed. The avg speed does seem to work fine. The search continues.

**blickcd** · 10-30-2019, 12:17 PM

Years ago I had problems with my cruise control not working all the time. The problem turned out to be that a mounting screw for the control lever was loose. I think the screw doubled as a ground connection.

To get to this screw you need to pull the steering wheel. If I remember correctly, when you do that, the key needs to be in the ignition, turned to the on position. Otherwise you will be pulling on the steering wheel for a very long time and it won't come off. How would I know that?

**DanZ3** · 10-30-2019, 04:26 PM

Worth a try cause everything else seems OK.

**95BMWIC** · 10-30-2019, 04:56 PM

Originally Posted by richardodn

If everything else has checked out, I'd bet the problem is the speed output connection from the cluster. That's the green connector pictured. All those ports with the same shape are electrically the same. You can use any one of them.

Not clear in your responses - did you check the speed output and make sure it was plugged in the proper position in the back of the cluster?

cluster.jpg

I didn't have cruise either (for a while) after I replaced the gears in my speedometer - I was too lazy to tear it apart and reconnect it

- I either forgot to plug it in or it wasnt secure .. dont recall - but it needs to be plugged in to work.

As above link posted for more info https://www.e30zone.net/e30wiki/inde...Cruise_Control

**DanZ3** · 10-30-2019, 08:17 PM

I replaced the control module with a known good unit, verified that both the brake and clutch switches are working properly, all connections including the speed input are connected, cleaned and tested the speed sending unit in the diff,verified that the cable is connected in the control unit. I’m hesitant to replace the control unit as it’s pretty costly. I have some electrical checks to verify based on some info that I found. I just need to keep looking.

**jbhl4** · 02-17-2020, 03:55 PM

did you ever get it to work.....I purchaed an e30 a while ago and everything on it worked except the cruise...I followed the owners manual and the posts on here about how to engage it..nope, nothing......One day, trying again, instead of pushing the lever forward once, twice..to engage it, I instead out of frustration pulled it back and presto! cruise control!....

**doctorx69** · 02-17-2020, 06:55 PM

it sounds like you already checked this... but in my case, the clutch was always contacting the kill switch... basically the kill switch was always engaged. I bent the switch holder a little and now it works.

**DanZ3** · 03-15-2020, 07:13 AM

Finally got the car on the ground after finishing winter projects. With salt gone I took the car out to test the cruise control. It works! The fix was inside the servo unit. There were 2 issues. First the sliding contacts inside that I assume send the controller some information were really dirty. Cleaned everything with contact cleaner. Second and likely the root cause was the slack in the cable. At some point the cable may have been replaced. Whoever installed it didn’t wind it fully on the spool. I wound it until there was less loose cable, adjusted the nut on the other end and now have functional cruise.