Problem retrofitting cruise control

Anssi

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I tried to retrofit cruise control to my 1999 2.8 Z3 with M52TU, since I believed it should work for that model simply by adding the interface module and the switch. I bought those, and put them on, but I can’t get the cruise control to work.

Now, there may be two possibilities:

1. The switch that I had bought, and which was supposed to be the right one (part number 61318360926) had an 8-pin connector, while the interface (65718380054) had a flat 6-pin connector. But since the switch looked right, and had the same amount of wires as the ones with 6-pin connector seem to do, I decided to try if it worked anyway, broke the connector and attached the wires together (they had same color codes, except one blue/green <-> blue.)

Maybe the switch was different, and does not work together with the interface after all? What do you think?

2. But, now I also noticed a post on this forum (on this thread https://zroadster.org/threads/retrofit-cruise-control.13617/) that apparently the cars made before 4/99 have “2 wire clutch switch”, which apparently is not a good thing. I don’t fully understand what it means, because both my English and my technical skills are not that good…

My car is made 2/99. So I guess the problem may also be that clutch switch thing.

So:

I quess I should first check which kind of clutch switch I have. How can I do that?

I appreciate any help, thanks! :)
 

petecossie

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There is information on cruise controls on here somewhere I'm sure, probably in the knowledge section. The cruise control switch you have purchased is for non fly by wire (plug and play) cruise control. There is a lot more to the installing of CC on the non fly by wire cars, actuator, clutch pedal switch, control unit, extra cable etc. I'm sure someone more knowledgeable on these matter than me will be along to advise you further.
I went through all this installation but as yet haven't been able to get the CC to work, not sure if the ECU needs to be informed via a reader that the system has been installed.
Good luck :thumbsup:
 

petecossie

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Dennisthemenace

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I fitted cruise to my 2000 m52tu 2.8 and it literally was plug and play, one thing though, if you have LED bulbs in your tail lights for the brake lights, it won’t operate, as it need to see resistance from the bulbs!
 

Anssi

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Here you go.

https://zroadster.org/threads/cruise-control-retrofit.20484/#post-344635

The thread/link you have in first post refers to this type of installation and shows all the parts required.
Hi, and thanks for your answer! :)

Actually it was your post somehere here that said:
"- M52TU duel VANOS engines. Plug and play, source the cruise control column stick and the small control module and plug it all in."

So I thought it would be plug and play...

I have understood that my car should be that easy one. Except for the possible clutch switch thing, which I still don't fully understand, and am looking for more information on that. :)
 

Anssi

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I fitted cruise to my 2000 m52tu 2.8 and it literally was plug and play, one thing though, if you have LED bulbs in your tail lights for the brake lights, it won’t operate, as it need to see resistance from the bulbs!
Thanks for the information, fortunately I don't have LED bulbs! At least I think so...? o_O

But that goes to show how you can get problems from little things that are very hard to figure out... :)
 

Anssi

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Here you go.

https://zroadster.org/threads/cruise-control-retrofit.20484/#post-344635

The thread/link you have in first post refers to this type of installation and shows all the parts required.
Ok, so now I figured out where the clutch switch is missing in my car, and found the clutch switch connector, that is shown in that wonderful post. :)

But this is still unclear to me: do I still have to get other things than the clutch switch (in addition to the interface and the stalk)? Since to my knowledge I have the M52TU with dual Vanos and fly-by-wire, which should be plug and play, BUT the car is built in 2/99, before the control functions and support systems changed?
 

petecossie

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If it's plug and play then with the correct parts it should work. I'm no expert on the Z3 roadster variants and CC set up for each one. All I can say is that CC switch you have is the same as the one I have the M Coupe non FBW set up. Not sure if the FBW set up CC switch is the same. I'm sure someone will come along to clarify it for you.
 

Stevo7682

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Definitely won't work without the clutch switch as the cruise control needs to know if you press the brake or clutch pedal so it will disengage
 

NZ00Z3

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Hi Anssi

I see that you have also posted your questions on Facebook with Randy Wright giving advice. He is very knowledgeable and helpful.

I will not be answering your PM as well as this post since your question is listed in this post.

1) The Switch
The switch supplier has sent you the wrong switch. It should have a 6 pin flat connector that plugs into the interface connection. You can either purchase the correct switch or continue to see if you can get the one you have to work.

To Test Your Setup
The interface is wired into the DME (engine computer) and you can see the operation of the different cruise control switches as digital inputs in the DME. You need a good scanner to be able to do this. Without a good scanner, you will be guessing that your wiring is correct and it will make fault finding very hard. Here are a couple of scanners that I know can do this.

- Foxwell NT530 with BMW software. Very good, reads all modules in the car. Buy only from a reputable supplier as the cheap Chinese knock-offs on E-Bay don't work. https://www.foxwelltool.com/wholesale/nt520-pro-scanner-with-bmw-software-installed.html


If you get a scanner, you can read the DME through the OBD11 port by the steering wheel (if your car has one). The DME and all other modules can be accessed via the 20 pin round port under the bonnet/hood. You will need an adapter cable to connect to the 20 pin connector. https://www.ebay.co.uk/itm/Fits-BMW...386334?hash=item2f01f65f1e:g:N0AAAOSwvKtY9kOF

If you choose to continue with the switch your have, let me know when you have a scanner set up and I'll guide you though the testing.

Is there a part number on the switch? This will give me a clue on which BMW the switch is from and how to set up the wires.

2) Clutch Switch
Link to the wiring diagrams for your 2/99 car https://zroadster.org/resources/1999-z3-z3m-electrical-troubleshooting-manual.13/

Drawings 6571.0-02 and 6571.0-03 cover the cruise control of your car.

Yes you have a 2 wire clutch switch. Make sure that you purchase the correct clutch switch for your car. You can find the part number by putting the last 7 digits of your VIN number into RealOEM and looking up the part. www.realoem.com

As others have said, your cruise control will not work when driving the car unless the clutch switch is installed.

Don't get too worried about the rev hang problem. You may not have it. Get the cruise control system working first and see.

There are two ways if fixing the problem:
- Getting the DME software for your car updated to the latest version. Your car may already have the latest version? There are 2 people in the BMW community that I know of that do this sort of work over the internet.

- Modify your car to a 3 wire clutch switch. An easy job to do. If you are really worried about the rev hang problem, maybe do this modification as part of your cruise control installation. I can provide details if needed.

Sorry about the long post, hope it helps

Regards

Murray
 
Last edited:

NZ00Z3

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Thinking about it a bit more, I would:
- put a clutch switch in and try it
- If it didn't work, get a scanner and start fault finding or get the right switch.
 

Anssi

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Hi Murray,

Thank you so much for your answer! I have also read your wonderful earlier postings here, and have had a lot of help from them too!

Yes, I posted the question to Facebook first, and later Randy answered there, so now I’m aware of the missing clutch switch. As you recommended, I will get that one first, it should be an easy and inexpensive thing to do.

If the cc still does not work, I will troubleshoot the control switch. They tend to be a bit expensive here in Europe, and all the used ones I have found are in US, so it takes several days, if not weeks - you’ll never know, to get them. So I’ll try my current one first, even though it makes troubleshooting more difficult.

I did not see the part number in my current control switch, and now it is already installed, so it’s hard to check better. I suspected that it might be 61311393315, since that one looks the same in pictures. I think I now managed to find similar electrical troubleshooting manual for that part, and if I got that right, it seems that it should work with the connections I made.

But anyway, the control switch will not be a big problem, because it can always be changed.


The rev hang problem was something I just came across yesterday, so I got bit scared of that. I tried to google the problem and a fix, but didn’t really find a clear explanation. Modifying my car to a 3 wire clutch switch sounds like a very good idea, if that is possible. So I’d be very grateful if you could provide details for that!

I really appreciate your answer. And don’t worry, everybody likes long answers... :)
 

NZ00Z3

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To convert your 2 wire clutch switch to a three wire clutch switch, you'll need to download the drawings for a later model Z3. Use these ones. https://zroadster.org/resources/2000-z3-z3m-electrical-troubleshooting-manual.11/

Compare drawing 6571.0-03 in both the drawings for your car and the later one. You will notice:
- The clutch switch for your car is 2 wire and the one for the later car is 3 wire.

- The connector numbers are different. X121 verses X11143. This may mean that you will need to install a 3 wire switch connector. Best found in a car wreakers/junk yard Z3.

- The wire positions are different in the connectors e.g. the earth wire is in position 2 on connector X121 but in position 1 in connector X11143. So you need to wire the connector X11143 correctly.

- You will need to add a power supply to connector X11143. You can either install a wire from the fuses as per the later car drawings, or you can source a power supply from some where near by. If you look at drawing 6325.0-00 in either set of drawings, you will find the brake light switch (S30). You can get a power supply from either of the two supplies going to the brake light switch. Terminal 1 or 4 of connector X78.

Once you have done the wiring of the connector, install the clutch switch and its done.
 

Anssi

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Ok, that seems pretty straightforward. I’ll start checking where I could find the X11143, and in the meantime install the switch normally (I should receive the switch in a couple of days) and see if there even is any rev hang problem.

You’ve been a great help, Murray, I don’t know how to thank you! But next time you come to Finland, I will buy you a beer. :beer :happy:
 

petecossie

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I said you would get some help from someone who knew the CC systems. This forum has such a breadth & depth of knowledge and to have Murray sort this problem out from the other side of the world speak volumes for how good this forum is.:thumbsup:
 

Anssi

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I said you would get some help from someone who knew the CC systems. This forum has such a breadth & depth of knowledge and to have Murray sort this problem out from the other side of the world speak volumes for how good this forum is.:thumbsup:

You are so right! I couldn’t own a car like this without having this kind of forum with helpful and knowing people all around the world to help maintaining it. Would be very hard to find someone with that kind of knowledge IRL, especially in a small country like Finland with not that many Z3:s. :)

And actually: I’ve found it’s much the same thing with my house, my computers, my guitar etc. I can’t imagine how people were able to do any DIY before the internet! :D
 
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