Covertible top wire harness breaking

[wilmk4]

Hi, I was wondering if y'all could help me with this. I happened to have my car checked out by my mechanic and there was another 2009 Z4 there becuase the wire harness in the covertible top had broken. I was told that BMW couldn't fix this issue and that it could happen at any time. Since then I have been really hesitant to put down the top. I would love to know how frequently this happens and if this is a high risk or more of a freak thing.

As a follow up - if it is common, how pricey and extensive of a fix is it? I know my mechanic can do it now but I will be moving cross country shortly and would like to be able to put the top down without a large dose of anxiety.

Thank you!

[bryanhoag]

Parts are not really the issue. It's the labor.

Harness replaced by BMW will be in the $4-5k range.

Does your mechanic know how to diagnose and fix these tops? If so, I'd love to know who your mechanic is. Though I'm assuming they're in Cali, based on your profile.

[RobbiZ4]

Originally Posted by bryanhoag

Parts are not really the issue. It's the labor.
Does your mechanic know how to diagnose and fix these tops?

Even with a lot of experience, replacing the roof hydraulic wiring harness takes a total of 11 hours. Additionally, if a hydraulic hose breaks, Murphy will stop the roof movement somewhere midway between a closed and open roof. The worst case scenario is if it leaks when open and in the trunk.
Even the required parts will cost more than 1k.

To be honest, every E89 hydraulic wiring harness breaks sooner or later depending on usage and the weather conditions of its surroundings.

This is my equipment, to diagnose and manage these issues:
https://z4-forum.com/forum/viewtopic.php?t=129048

[bigendbob]

Just fix it, splice in new wires. Have had to do twice in last couple of years on my 12 year old car. Hard part is finding the break.
First obd reader gets you somewhere near, then some dressing pins poked into wires and multimeter to find break.

Part of the fun provided by BMW Z4 ownership.

[RobbiZ4]

Originally Posted by bigendbob

Just fix it, splice in new wires. Have had to do twice in last couple of years on my 12 year old car. Hard part is finding the break.
First obd reader gets you somewhere near, then some dressing pins poked into wires and multimeter to find break.

Can be done this way for yourself, but not for others if you already know additional breaks will occur.
And there is no guarantee that the wires will break first. I've also seen E89s with hydraulic hoses broken first.

[bigendbob]

Main problem i think just 1 in 100 owners capable of any DIY.
Therefore lots of expensive repairs that shouldn't be.

My business partner had a first generation Z4.
She had never lifted the bonnet/hood to top off the washer bottle. She said the annual check at garage did it.
She didn't know where the release lever was fitted.

[RobbiZ4]

Originally Posted by bigendbob

Main problem i think just 1 in 100 owners capable of any DIY.

But these roof issues are challenging, even for experienced mechanics. As this roof mostly stops finally in case of an issue, nobody is able to close it or bring it into a position get it repaired.

That was the reason, why I've developed this Y3 Roof Diagnostic System: to identify the exact source of an issue and to be able to override a faulty component. The latter is the most important benefit of it.

[airmarc]

I had my harness repaired at Hendrick BMW Northlake here in Charlotte. They were able to inspect and repair and replace the frayed wires in the harness. They did mine for about $1200 in Labor. Vs the $4k-$5k for a brand new harness.

The technician cautioned that replacing hydraulic lines (which are part of the harness) can cause more harm than good if they don’t need to be replaced. In his professional opinion a wiring repair in the manner that he performed it would be a more cost effective and better long term solution for me. The technician replaced new wires for the full length of the moving sections that go between the fixed points of the convertible top.

And I agree with the above, this will happen to all Z4s. So I will continue to inspect those areas of the harness which frayed before.

Hope this helps!

[bryanhoag]

airmarc please see your PM!

[bigendbob]

Originally Posted by airmarc

I had my harness repaired at Hendrick BMW Northlake here in Charlotte. They were able to inspect and repair and replace the frayed wires in the harness. They did mine for about $1200 in Labor. Vs the $4k-$5k for a brand new harness.

The technician cautioned that replacing hydraulic lines (which are part of the harness) can cause more harm than good if they don’t need to be replaced. In his professional opinion a wiring repair in the manner that he performed it would be a more cost effective and better long term solution for me. The technician replaced new wires for the full length of the moving sections that go between the fixed points of the convertible top.

And I agree with the above, this will happen to all Z4s. So I will continue to inspect those areas of the harness which frayed before.

Hope this helps!

$1200, think i will give up my day job and fix roofs!

[wilmk4]

Originally Posted by airmarc

I had my harness repaired at Hendrick BMW Northlake here in Charlotte. They were able to inspect and repair and replace the frayed wires in the harness. They did mine for about $1200 in Labor. Vs the $4k-$5k for a brand new harness.

The technician cautioned that replacing hydraulic lines (which are part of the harness) can cause more harm than good if they don’t need to be replaced. In his professional opinion a wiring repair in the manner that he performed it would be a more cost effective and better long term solution for me. The technician replaced new wires for the full length of the moving sections that go between the fixed points of the convertible top.

And I agree with the above, this will happen to all Z4s. So I will continue to inspect those areas of the harness which frayed before.

Hope this helps!

Out of curiosity, my 1998 SLK230 had a hydraulic issue and I just assumed that this would be fixed in future convertibles. Is the only safe convertible one that is either a manual roof or a roof that is one piece that has to be taken on and off (thinking of my friend's old MG).

Is there any benefit to not using the top as much?

Thank you all for your help!

[bigendbob]

I have used my Zed roof daily during summer months last 9 years. Possibly 3,000 cycles.
It breaking just a chance you take, why have the car otherwise.

[surfwooder]

Since buying my 2009 Z4 5 years ago, I've not had a serious top problem. I am a older owner (73) with many years of being a electronics engineer under my belt. Plus, years of troubleshooting complex problems within various Naval aircraft. I have also found the main problem with fixing/troubleshooting roof problems in the E89 top system is lack of a real point to point wiring diagram, and other full documented manual. I would use a Bentley Manual, if one was available. In 2009, Congress allowed all the "Right to Repair" legislation to expire. Prior to that happening, all companies had to provide repair information for publication. This included cell phone companies, through auto manufactures. Some European countries still require auto companies to print a shop manual, but only in the local language, and not for export. I've found BMW watches many of the American, English forums for people who post information which they feel is to close to what a manual would include. When searching for a item you'll get "This information is Forbidden. by BMW NA. You may be able to find a "work around" just look for part numbers from your Z4, to another hardtop convertible much like your own Z. Look at the hydraulic top operation of the 2008 328IC. The 328IC Bentley Manual give point to point wiring to and from each sensor through the Convertible Top Module. Both cars share the very same CTM, as to part number. Pin out is the same on the sensors plug on both cars module. So, while checking the pin voltage, and knowing actual position of the sensor, you can predict what signal should be at a testing pin. But the roof must be up for you to get to the CTM on either car, since the module is located below the floor of the trunk.

[bigendbob]

Manuals and wiring diagrams.

https://z4-forum.com/forum/viewtopic.php?t=119914