Roof Shell 2 stop closing, throw fault code A68B - my way to upgrade wiring harness

[cra3y]

Disclaimer: I'm not native English speaker, please forgive me my lingual mistakes Thanks!

Hi
I had problem during closing roof process - the roof pack 2 (one with the glass, which open first/close last) stopped just before reach back lid and throw the fault code A68B, which means: "Microswitch, roof shell 2 closed, left"





I disconnected this switch and tested with multimeter:
- it has 0.05 Ohm when not pressed
- it has about 2.7 kOhm when pressed, so this switch is OK

This led my suspicious to cable and bingo ! The one was broken near upper hinge mechanism (image below):



This cable is very stiff and prone to crack, when You try to bend several times. I don't know, why BMW use this poor quality cables in such demanding places (when bending is very often). The red "oval" is the place, where cables is broken.




I cut the cable and replaced with new (temporailrly) in this section to check it will work or not.


And this fix works !! But ... My plan is to order good, industrial-grade 2 or 3 or more wires cable like chainflex® CF9 (https://www.igus.co.uk/product/1013) which will able to withstand 5 000 000 bending cycles or more and replace existed ones (in both sides) in this area (images below) to prevent such problems in the future (because bending an tensions occurs in this area very often and existing wires will be broken sooner or later):

[cra3y]

I bought complete roof arms with hydraulic and electric harness (with sensors and microswitches too) to scavenge connectors, sensors (hall sensors - yes! the expensive ones), microswitches, hydraulic tubes and wiring harness for future usage and to learn, how to fix this damn thing .

Before I started, some info - Dach1 is the main roof shell, that dock into front, Dach2 is the secondary roof shell, with heated window in the back:


Below is my short analysis of the weak points (where cable bends to much) in roof construction:

1) movement of Dach2 - the red "ovals" pinpoint the weak points. These bending points cause cable to bend over 160 degrees!

a) Dach2 is stowed on Dach1


b) Dach2 is in on transition to closed position (on the back lid)


c) The transition of Dach2 is completed and Dach2 is stowed on back lid.



2) movement of the whole pack (Dach2 and Dach1) into the boot section.

The following photos are from this section:



a) Dach2 is stowed on Dach1 - both in upper position - view from inner side of hinge



b) Dach2 is stowed on Dach1 - both in lower position (stowed in the boot) - view from inner side of hinge



3) My plan is to upgrade cable situation on these weak points to fix this for good:

a) I bought industrial-grade electrical cable: chainflex® control cable CF9 CF9.05.02 (2 wires 0.5mm2) and CF9.03.05.INI 52 wires 0.34mm2)

b) Prepare to replace the existing cables wires in this sections (cut existed one, solder in both side then wrap soldering sections using heat with shrinking tubes)

Left side of car:
- first cable section (2 wires):


- second cable section (2 wires)


On the right side of car - the same way, but there is another cable harness with 5 sensor/switches wires in small diameter and 2 with large diameter. The 2 large is for driving Dach1 motor-latch in the front, and these wires should withstand bending, but I'm thinking about replace the 5 wires in the same section as photo above.

4) My big concerns about the upper section of the Dach2 hinge

I have big concerns about the section marked in "A".



The hydraulic tube bend hard (over 160 degrees and stretched a bit) in this section, when Dach2 is stowed on the back boot lid:


I modified the harness situation by make more freedom in this section:


And how this look like, when Dach2 is on the way to Dach1 (to stow on the Dach1)





The bend is about 90-100 degree (before was about 160-170) and electrical harness + hydraulic tubes should withstand longer than before.

.

Time to apply modifications (mentioned above) in my car :-)

[NoQuarter]

Well done Chris!

[RobbiZ4]

Great job!

A copy has been placed in the German ZRoadster forum:
http://www.zroadster.com/forum/index...arness.133708/

[cra3y]

Update: I replaced 3 pair of wires today: to microswitch left, right and to hall sensor (all in Dach2)

Wires were connected by using "Western Union" splice then clenched using small metal tube. Both wires were isolated by tape then isolated from environment using temp. shrinking tubes with glue.




Left side:




Right side:

[cmm542000]

Thank you for all the help and illustrations! Can you tell me how to get the top up like that when it is inoperable? The top hasn’t locked down in the back only the front at the windshield but I can only raise the rear top about 6 or 8 inches. I had to fish a rod through the hinge opening just to get the trunk open via the emergency release.

Thanks!

[RobbiZ4]

Hi,
If you unlock the 2 messing screws on the hydraulic pump, you should be able to raise the roof shell.

Unlock means turn it only 1/2 or 3/4 as the screws are secured and cant be removed without destroying the pump!

Move the shell as well as the trunk lid always only with 2 persons from both sides of the car against the hydraulic pressure to avoid torsion in the mechanics.

Where are you from?

[Romer]

I had the same fault code. The top was up and couldn't move, the trunk won't open and the windows would not go up. Driving it the Red light was flashing and beeping.

Took it to a shop and they said there were broken wires and it looked like it was repaired before , but it was a hack job. So I have them redoing the harness to make it right

Since I was unable to open the top or get in the trunk after searching, I decided it was best to take it someplace

To the author, your thread is awesome and wish there were more posts like this here. I also wish I could have moved the top so I could have taken a crack at this. Thanks for documenting your process

[RobbiZ4]

Originally Posted by Romer

To the author, your thread is awesome and wish there were more posts like this here. I also wish I could have moved the top so I could have taken a crack at this. Thanks for documenting your process

Well, open translate.google.com, enter the german zroadster forum and you will find nearly everything you are looking for.

E89 forum:
https://translate.google.com/transla...neue-e89.32%2F

The same posting in English as well in the German forum:
https://www.zroadster.com/forum/thre.../#post-2773183

My tips and tricks link page:
https://translate.google.com/transla...23post-2743419

[Romer]

Thanks Robbi. I had a shop do it. The ended up rebuilding and replacing the harness

[DK.]

Does this happen on the e93 because I got the same code

[DavesZed]

Originally Posted by DK.

Does this happen on the e93 because I got the same code

Yes it does. Although you have an extra section it's all on the same principle with the same connections

[RobbiZ4]

Originally Posted by DK.

1) Does this happen on the E93 because I got the same code

Originally Posted by DavesZed

[2) Yes it does.

1) Yes and 2) No!
Even if the E93 roof is working similiar compared to an E89, the same fault codes do have different meanings!

[DavesZed]

Originally Posted by RobbiZ4

1) Yes and 2) No!
Even if the E93 roof is working similiar compared to an E89, the same fault codes do have different meanings!

Attachment 2977437

Why would BMW use the same fault code for two different faults where the same faults can occur on both models? Bit stupid and short sighted of them.

Although, technically, I wasn't actually wrong in my reply, this CAN happen to the E93 just as much, if not more with the extra section.

[RobbiZ4]

Well, it's weird. The same code has a different meaning on the following cars: E89, E64, E93, Mini R57, R59

[DavesZed]

Originally Posted by RobbiZ4

Well, it's weird. The same code has a different meaning on the following cars: E89, E64, E93, Mini R57, R59

Attachment 2977532

Although some do seem "similar"

[bigendbob]

Seems like you created a lot of work for yourself when only needed to splice in some new wires.

[okanfx]

[QUOTE=cra3y;23645941]Disclaimer: I'm not native English speaker, please forgive me my lingual mistakes Thanks!


I disconnected this switch and tested with multimeter:
- it has 0.05 Ohm when not pressed
- it has about 2.7 kOhm when pressed, so this switch is OK

This led my suspicious to cable and bingo ! The one was broken near upper hinge mechanism (image below):


I am replacing the same micro switch (Left, shell 2)

I bought a brand new BMW micro switch online, and first tested it for continuity and the multimeter did not beep, pressed or not pressed.
So I thought maybe it was DOA. Then after seeing your post I tested for ohms and ohms changes when I pressed the button. Is there a pull up resistor in the switch? But my main question is the switch I got is good to go replace the one in the car.

Then I tested for ohms, and I am getting
- it has 0.05 kOhm when not pressed (in your post you wrote Ohm, not kOhm)
- it has about 2.7 kOhm when pressed.

[okanfx]

[QUOTE=cra3y;23645941]

I disconnected this switch and tested with multimeter:
- it has 0.05 Ohm when not pressed
- it has about 2.7 kOhm when pressed, so this switch is OK

This led my suspicious to cable and bingo ! The one was broken near upper hinge mechanism (image below):


I am replacing the same micro switch (Left, shell 2)

I bought a brand new BMW micro switch online, and first tested it for continuity and the multimeter did not beep, pressed or not pressed.
So I thought maybe it was DOA. Then after seeing your post I tested for ohms and ohms changes when I pressed the button. Is there a pull up resistor in the switch? But my main question is the switch I got is good to go replace the one in the car.

I tested for ohms, and I am getting
- it has **0.05 kOhm** when not pressed (in your post you wrote **Ohm**, not **kOhm**)*************
- it has about 2.7 kOhm when pressed (I am getting similar to this)

...Note.. I am able to raise/close the convertible roof by unplugging pin 7 wire and putting a jump wire (pin receptacle contact attached) into that socket position 7 and a needle at the end of that jump wire going behind pin 10 copying the signal from the right microswitch.

[B21]

I understand the micro switches have a resistor in part of the switch to differentiate between a disconnected micro switch and a broken one…

Robbie is your man..

[bigendbob]

Seems every switch and relay has a open circuit resistor fitted.
Mechanical switches will vary with ohms.
Hall switches the current changes.

[okanfx]

Originally Posted by B21

I understand the micro switches have a resistor in part of the switch to differentiate between a disconnected micro switch and a broken one…

Robbie is your man..

That makes sense. When I tested the wires in the trunk unplugged /pins 7 and 20 coming from the current faulty micro switch, they beeped for continuity when the roof was closed. None of the other pin pairs beeped.
Because of this I assumed the wires from the micro switch must be intact and it must be the switch which is broken.