Another Roadster Roof Thread

codude · 06-01-2023, 09:54 AM

...but slightly different than the ones I could find.

The history:
Bought the vehicle as salvage with a vandalized top. Pulled the top assembly, replaced the soft top, and reinstalled the assembly. I did NOT have the drain issues many report, everything was clean and dry in the motor cubby. Operated the motor forward and reverse off of a 12 volt battery and it worked great.
Reinstalled the top assembly.

The now:
Using the button, the motor lifts the top from the retracted position to the "roof up" position just fine, and the latch motor engages and locks into place. No issues at all. Except that the little red light blinks.
HOWEVER, the "lower roof" button does absolutely nothing. the locks don't disengage and that motor does not run at all. Neither does the actual top motor. Nothing. Crickets.
I can lower manually by releasing the red doohickey in the trunk, re-engage it and the top will lift automatically all day long. But it won't go down, and that pesky red light just blinks no matter what.

From reading forums extensively, it sounds like the compartment microswitch in the back will throw an amber light if it's out of position or having issues. Visual inspection seems fine, and I tried jumping the wires just to see if that made a difference. No dice.

I have a Foxwell reader with the BMW software and the top throws fault 25:
CVM: Switch, convertible top stowed, short circuit to ground.

On a related note, some posters have mentioned the E85 top "locking" into the down position. I don't see what it would lock into, but since I'm lowering it manually the lock motor never engages and the lock "forks" stay disengaged (straight out). Not sure if this could throw a code or how to correct it.

The short of it:
Both motors work fine as I can raise the top and engage the locks perfectly.
The compartment microswitch test also seems to have passed.
I don't know how the wiring works, but I assume that the control module just just reverses polarity to lower vs. raise the top, so if the wiring to raise the roof is good, it should be fine to lower also.

Thanks for any input- This one has me stumped.

zed_fan · 06-01-2023, 11:55 AM

Probably issue with the hall effect sensors which tell the computer if the top is up or down.

see https://www.pelicanparts.com/techart...rtible_Top.htm starting at figure 11. Inspect your wiring there for maybe obvious damage. Best bet is to monitor the roof sensor statuses as shown in that link but not sure if your scanner is advanced enough for that.

Clearancediver · 06-02-2023, 01:23 AM

I would replace the trunk shelf switch despite you shorting it to ensure it works… and ensure that the shelf is fully down and the “turn handles” (brain fart on proper word) to ensure that shelves are down and locked into the “down” position. Try the 2nd thing first before doing the 1st thing….

JAS1169 · 06-12-2023, 05:37 PM

You replaced the canvas top correct?

The top has a wiring harness which runs down the roof and finally plugs into the white box behind the driver's seat which is the convertible controller. This same wiring harness has two sensors on either side of the front plate of the top which meets the frame of the windshield.

I strongly suspect you may have either snapped a wire to one of these sensors or dislodged a sensor when changing out the top. In that, others have post similar problems after changing out the canvas top of their cars. In almost all of these prior postings the problems involved issues with the wiring harness or dislodged sensors.

06-01-2023, 09:54 AM	#1
codude Registered 0 Rep 1 Posts Drives: 2007 BMW Z4 3.0i Join Date: Jun 2023 Location: Morrison, CO iTrader: (0)	Another Roadster Roof Thread ...but slightly different than the ones I could find. The history: Bought the vehicle as salvage with a vandalized top. Pulled the top assembly, replaced the soft top, and reinstalled the assembly. I did NOT have the drain issues many report, everything was clean and dry in the motor cubby. Operated the motor forward and reverse off of a 12 volt battery and it worked great. Reinstalled the top assembly. The now: Using the button, the motor lifts the top from the retracted position to the "roof up" position just fine, and the latch motor engages and locks into place. No issues at all. Except that the little red light blinks. HOWEVER, the "lower roof" button does absolutely nothing. the locks don't disengage and that motor does not run at all. Neither does the actual top motor. Nothing. Crickets. I can lower manually by releasing the red doohickey in the trunk, re-engage it and the top will lift automatically all day long. But it won't go down, and that pesky red light just blinks no matter what. From reading forums extensively, it sounds like the compartment microswitch in the back will throw an amber light if it's out of position or having issues. Visual inspection seems fine, and I tried jumping the wires just to see if that made a difference. No dice. I have a Foxwell reader with the BMW software and the top throws fault 25: CVM: Switch, convertible top stowed, short circuit to ground. On a related note, some posters have mentioned the E85 top "locking" into the down position. I don't see what it would lock into, but since I'm lowering it manually the lock motor never engages and the lock "forks" stay disengaged (straight out). Not sure if this could throw a code or how to correct it. The short of it: Both motors work fine as I can raise the top and engage the locks perfectly. The compartment microswitch test also seems to have passed. I don't know how the wiring works, but I assume that the control module just just reverses polarity to lower vs. raise the top, so if the wiring to raise the roof is good, it should be fine to lower also. Thanks for any input- This one has me stumped.
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06-01-2023, 11:55 AM	#2
zed_fan Private 21 Rep 70 Posts Drives: 2006 Z4MR, E60 M5 6MT Join Date: Jul 2020 Location: AZ iTrader: (0)	Probably issue with the hall effect sensors which tell the computer if the top is up or down. see https://www.pelicanparts.com/techart...rtible_Top.htm starting at figure 11. Inspect your wiring there for maybe obvious damage. Best bet is to monitor the roof sensor statuses as shown in that link but not sure if your scanner is advanced enough for that.
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06-02-2023, 01:23 AM	#3
Clearancediver Lieutenant 90 Rep 406 Posts Drives: 2004 Z4 Join Date: Oct 2012 Location: Victoria, BC Canada iTrader: (0)	I would replace the trunk shelf switch despite you shorting it to ensure it works… and ensure that the shelf is fully down and the “turn handles” (brain fart on proper word) to ensure that shelves are down and locked into the “down” position. Try the 2nd thing first before doing the 1st thing…. __________________ Sent from my smart phone...
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06-12-2023, 05:37 PM	#4
JAS1169 Private First Class 50 Rep 156 Posts Drives: BMW 2003 Z4 Join Date: Sep 2017 Location: Mechanicsburg, PA iTrader: (0)	You replaced the canvas top correct? The top has a wiring harness which runs down the roof and finally plugs into the white box behind the driver's seat which is the convertible controller. This same wiring harness has two sensors on either side of the front plate of the top which meets the frame of the windshield. I strongly suspect you may have either snapped a wire to one of these sensors or dislodged a sensor when changing out the top. In that, others have post similar problems after changing out the canvas top of their cars. In almost all of these prior postings the problems involved issues with the wiring harness or dislodged sensors.
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