E89 Z4 convertible top harness

image Let the fun begin,,,,E89 Z4 with hard top convertible,,,,the convertible top stopped working,,,,so I had to open the rear trunk with the computer and release the hydraulic pump pressure,,,,so I can move the top panels,,,to gain access to the top harness and hydraulic lines,,,you have to remove all the rear trunk panels.image Next to the battery is the hydraulic pump and relay,,,the new harness  comes with new hydraulic line,,,,so I also have to bleed all the lines once the job is done.image So the best way to get to most of the harness was to stack the two panels on top of each other,,,,since I released all the pressure in the system,,,I can manual move each panel to gain access to the wiring harness and lines,,,which run on both sides of the convertible top.

This entry was posted in Uncategorized and tagged , , , . Bookmark the permalink.

37 Responses to E89 Z4 convertible top harness

  1. Tyler says:

    I need to replace my harness – where’s the rest of this post? Please help.


    • Sorry that all ,,,,that was such a big job and a pain in the ass I just gave a brief idea what this job was about,,,,,and to get pictures wasn’t easy,,,,the best thing I can tell you when removing the harness and hydraulic lines you should follow in with the new one right behind it,,,,so you follow the same routing path.,,,,take pictures or video of the layout of everything,,,I can tell you there is no repair manuals from BMW on this job,,,,they didn’t even know how much to pay me because there was no labor operation on this job.


  2. mike cundiff says:

    I can relate to your frustration, my top stopped working so I took it to a foreign auto repair shop that had been in business since the 70’s. I thought they would do a good job. HA!!! got it back worst than it was when it went in. They said it needed a new pump motor. So I bought one and replaced it myself carefully labeling every line to the numbered port on the pump. I have a schwaben obd tester especially designed for bmw so I got the system reset and wow. cylinders started acting all crazy. My best guess is that they got the lines switched around. Now I have no idea which line goes to which numbered port on the pump. I know this is a long shot but do you have it wrote down somewhere which lines on each cylinder go to which numbered port on the pump unit? I have poured through forums youtube vids and downloaded every BMW repair manual available to try to find this info. It’s nowhere to be found. I have the 09′ z4 e89.


    • Oh my god I feel for you,,,,I’m sorry I did not write anything down,,,,I replaced and rerouted the pair of hydraulic line to each cylinder one at a time so I wouldn’t have this problem,,,,,BMW doesn’t have a hydraulic schematic for the lines,,,,I hate to say this but if you can find the same car and comparing your car to the good car


      • Tyler says:

        Mine was a 2011, but when I switched everything out, I noticed that the lines and the pump had corresponding numbers on them. They’re kinda hard to see, but they were there. After pulling my back out, I at least got the pump working, but it was quite the ordeal. Good luck.


  3. mike cundiff says:

    thanks for the feedback guys. I really do not know anyone else with the same year model and make of mine that I could compare it to. Tyler I will look harder to see if I can see line numbers. If I can figure this out I will post it on all the forums so the info will be out there. Thanks again for the feedback.


  4. Stuart says:

    I have to replace a leaking line on my 2010, do they self bleed or is there a certain procedure for it.


  5. Bryan Hoag says:

    BMWTechnician, I’m starting to develop an issue with my Z4 convertible top. I think its a harness issue. Are you still repairing these? I’d rather pay someone to do it right than mess around with it myself and make the problem worse.

    Liked by 1 person

  6. Bryan Hoag says:

    Where are you located? Any chance you can contact me directly at bryan.m.hoag@gmail.com?


  7. Hampus Bergman says:

    I have some question about the Z4 e89 roof.
    Is there a posibility to use that cool looking hydraulic roof system on an other car as an hot rod?
    I have tried to read instruction manuals how to drive the roof without K-CAN and CAS. Does IT work?
    Do you think there is a possibility to use the CTM (convertible top module) in an other car?
    What happeneds if I just power the relay directly from the battery? Does it make the full sequence whitout any computer?

    That was meny strange question 🙂

    Best regards


    • You probably could make it work with a lot of fabricating,,the motor with pump has some relays and a control module which see and monitors the convertible top sensors,,,,you would also have to put latches and sensor above the windshield so it knows when to unlock and lock the top….anything is possible with a lot of work and engineering.


      • Hampus Bergman says:

        Thanks for answer,

        Do you think the electrical system would work?
        My biggest concern is if I can manoeuvre it outside the original car.

        Best regards


      • I don’t think you can man oeuvre the top outside the car,,, the electrical should all work as one unit with the top,,,this will not be a easy job,,,,but I can see it working with a lot of work and electrical knowledge,,,,this job will be a lot of work,,,not a easy swap over,,,I would stay away from it.


  8. Shawn says:

    Can you please post the procedure for releasing the hydraulic pressure on the hydro unit?




  9. Will Dockerty says:

    How common are leaking hydraulics in the e89 roof?


    • Not very common,,,why what’s going on


      • Will Dockerty says:

        Reason for the question, I recently bought a 2009 e89 Z4 2.3i (118k miles) and on the 3rd day of ownership it sprung a hydraulic leak when lowering the roof, covering the passenger seat and trim in oil. Luckily, the trader I bought it from took the car back and refunded me. I loved the car and am looking for another, but am very nervous about it happening again with it being a very expensive and complex repair.


      • That’s good they took the car back,,,,and it’s not common for a hydraulic leak,,,,more common would be the convertible top wiring harness getting damaged or getting pinched over time.


  10. Rahul satoskar says:

    How to open the roof panels …i released pressure but the roof is still locked not moving a bit when pushed ……..


  11. George James Ramos Jr. says:

    Hello. I am having a similar issue. What is the front cowl lock? I am having the issues with a 2011 E89. I am trying to unlock the roof so I can access the wire panel. I am planning to inspect the wire as my roof gets stuck and won’t open.


  12. Larry Hamilton says:

    I am having the same roof problem with my 2016 Z4 (purchased in early 2017). It has about 60K miles on it. They diagnosed it originally as a bad ground wire and quoted $700 to repair. One day later they said it was the roof harness and want $6,500 to repair. I complained to the service manager and he contacted BMW corporate about a “good faith” assistance possibility, given this car is only 4 yrs old. He called me back and thinks they may be willing to help with the expense. I should hear back in a couple of days. Just FYI that this is happening to the newer models as well.


    • It shouldn’t cost $6500 that’s just crazy,,,,I’ll do that job all day for that price,,,I think the harness is about $400 to $600 and the labor is about 15hr.


    • Steve Ackerman says:

      I have a 2015 Z$ that the roof isn’t working. Went to dealer last week, was told it was a sensor. Just got off the phone with them and now its the whole harness needs to be replaced. $4700!!! Told them to get the roof closed like it was when I brought it to them. not paying that much for a wiring harness!


  13. Alymon says:

    Well, looks like I am having a similar issue. Took my 2015 Z4 to the dealer for service because it kept telling me there was an obstruction when opening/closing the roof. First they told me it was a connection between the wiring and charged me around $250 to fix it. Worked fine for a couple of weeks, then it got stuck again. Took it in, they said they fixed it, didn’t charge me the second time. A few more weeks go by and now they are telling me “WIRING DAMAGED IN CONVERTIBLE TOP HARNESS” and want $3,500 to fix it. Pretty frustrating.


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.