How does the @#! cab power roof work?

[Chris Lovell]

Does anyone know the sequence of motorized steps in the opening and closing of a cab roof? Or know of anywhere this is documented (not Bentley or 101)? I would like to first understand the electric cab roof sequence of actions, and then try to get it working. (My problem is that one of the locking motors does not fire regularly) If this fails, I would like to convert to manual operation.
Can anyone help with this? I am very frustrated with this #*$#!! roof. Luckily I have a long winter in New England to recover.
Thanks,
Chris

[AFJuvat]

OK, in a few easy steps Kind of like a computer programming flowchart:

1. Button is pushed to open top - IF microswitches in top are depressed AND upper OR Lower microswitch on passenger side transmission is NOT depressed, THEN rotate locking motors to open position. Microswitches Inside locking motors send signal to turn "top is up" warning light on.

2. IF Microsiwtches in top bar are open AND microswitchs on passenger side transmission are not depressed, turn on electric motors in back of car, retracting top.

3. IF bottom microswitch on passenger side transmission is depressed, AND Microswitches inside locking motor indicate latched unlocked, AND microswitches on top bar are open THEN Stop cabriolet top retracting and turn off "top is open" light

To Close:

Button is pushed: IF # 3 above still applies, turn transmissions the other way. Until one of the following happens.

1. Top microswitch on transmission top is depressed - top stops immeditely, regardless of top position

2. IF microswitches in top bar are depressed AND top microswitch on transmission is NOT depressed, turn locking motors to 'Lock" position until internal microswitch in locking motor indicates "lock", then turn out "top is open" light.

Your problem with your top is you have a bad locking motor - it is not sending the proper signal to secure your top. They are easy to replace - but unfortunately a bit pricy.

AFJuvat

[Chris Lovell]

That is very helpful and, believe it or not, takes some of the mystery out. Could you give me some idea how to get to the front locking motors and micro switch? How to remove the roof front edge trim plate (behind which the motor and switches live) is not at all obvious to me.
Thanks again.

[AFJuvat]

Easy enough to do. You will need a phillips screwdriver and a 5mm allen wrench.

On either corner of the top bar, you will see 2 phillips screws - remove them. If you have an older cab (80s - early 964) - you have the "grab handles" on either end of the bar - the handles are NOT removable.

After teh phillips screws are removed, the cover is just held in with spring clips - tug on the padding covering the bar - it should come off - you may have to work it around the grab handles if you have them.

You will then see the locking motors and the microswitches (the switches are those plastic rollers you see on the front of the bar, just outside of the locking motors) The microswitches themselves rarely go bad or need replacement. Where you have your problem is in one of the locking motors - on the older motors, the switch inside it wears out - thus not giving the proper signal to open or close completely. on the later cars - (late 964 - 993) the brass gear inside the motor shears a tooth or two off, causing the same problem.

WARNING!!!: Use extreme care removing the locking motor. In the process of removing it (with the top up) you will have to use the switch to open or close the top partially. If one locking motor is moving slower than the other, the transmissions may still get the signal to start moving before the locating pins have cleared the windshield frame. Watch the top carefully and STOP if one side snags on the windshield frame.

AFJuvat

[bigchillcar]

any reason why after installing a stereo last night (forgot to disconnect negative terminal), removing tons of wild wiring from a previous, very intricate install job...all working witht he top down for convenience..when i put the top back up, my cab warning light is on and won't extinguish. i've just bought the car and haven't put the top down myself before last night. could i have missed a 'locking step'? i just used the button to 'lock it down'. is there a final step that would extinguish the bulb? on a related note - i also have the airbag/seatbelt warning lights on now, too.. see thread on the 964/993 forum..
ryan

[kuehl]

They did make CD video on it.

[dorschman]

hey ryan- Is there any connection between the new stereo and the accessory position for ignition? Maybe that could send a strange signal if someone previously spliced into the accessory cable for a stereo? Just a thought.

[bigchillcar]

hey guys - all i had to do was cycle the top back down and up and the light extinguished.. one down, two to go..
ryan