Porsche 964 Cabriolet Top wont work
 

I bought a 1990 Cab a bit ago and its working excellent. Tight car. Tight top. No leaks. Very happy and only into it with fresh service and about a $3000 service bill with new oil lines for $15000 cdn. So I did well I think.

However I'm having some top opening issues and thought I would ask for some common issues/solutions to save my repair guy some time and me - money - starting from scratch.

Top motor works....but long term plan is I don't really want to use it as I know if the bow bends its serious money to replace.
My plan is to just use the release motors and then manually open the top.

I opened it manually (disengaged the up/down motors). The mechanism is good.
Unlatched manually with a power screwdriver - the motor gears are good, and so are the integral microswitches. Used a power source on the motorized latches. They work, open and close. But the latching motors are not getting power so it’s either the brain or one of the microswitches.

The Porsche 964 (4 pin) Convertible Top Control Unit part number - 911 618 313 01 I had taken apart and re-soldered. The latches still aren't opening.

So I figured I would ask you all before buying a new Control unit, as they are about $300.

Thoughts?
Sean in Vancouver

Hi. The top opens and closes in two stages.
To open, first the clasps just above the windshield on both sides are activated and release the leading edge of the top. This is the first stage. Then, the second stage: motors located on rear seat wall are activated and power the transmissions which open the top.

To close, the reverse happens: motors on rear power the transmissions which rotate opposite way and slowly lower the top over the windshield and when a sensor "sees" the top in its correct position then the clasps take over and secure it down tight.

Are you saying the initial opening clasps are not releasing the top when you push the button to open?

yes. its the first stage. Sorry I waited so long to respond

I have noticed that on mine, the wires feeding the clasps are becoming worryingly brittle.
They run on the right side of the roof. When the roof is open you can see at the bottom right of the solid back part of the roof. They are in a black sleeve. In my case the black sleeve is already torn.

For insights, read here under 'Porsche Cab Top': http://www.systemsc.com/problems.htm

Trouble after trying to close with cover attached.
 

I had the cover on with roof down and battery out, placing the battery back in triggered my alarm which in turn closes the roof and windows, with the cover still on the roof failed to close. Now it won't do anything.... I am hoping there is a trip switch for when this happens?? Any help would be greatly appreciated! Cheers, Nick

Yep, check the fuse.
Good luck
Günter

I have a top control module. Let me know if you want it . I have two actually. Bought one thinking first was bad. Not the case. Now have a targa.

Thought I would add a question to this thread as it seems there is some good experience on 964 cab roofs. I had the latch issue so I loosened the bolts on the motors so I could open the top as it would not latch shut. Covered it, drove it until I got a new top ECU. The ECU seems to have fixed the latching issue but now the motors that open and close the top don't seem to engage so the top won't open or close automatically. I tightened the bolts but the motors try to move the top then disengage. If I close it manually the latches engage and disengage properly. Is there a trick to taking the top out of "manual mode"? I hope I didn't create a new problem. Any advice will help here.

I read these posts and thought back to the dread that I had when raising and lowering my top resulting from similar issues with the header motors and the dreaded main beam failure. About two years ago, I converted my top to "full manual" operation, using the DC Automotive conversion kit and disengaging the motors that raise and lower the top, and now have stress free convertible top operation. Problem solved!

I reached this point after owning my 964 cab for 13 years because, at least 1/3rd of the time, the header panel motors were out of synch and one motor would pull the top down onto the windshield header panel but I couldn't completely close the top because the other motor was out of synch. I learned that replacing the motors would be quite expensive (~$1,000 each) and doing so is only a temporary solution as they will eventually fail again because they're electrical motors placed where they will get wet (they're covered from above only with the fabric of the convertible top).

The DC Automotive conversion kit consists of two L-shaped handles from a Targa top and the corresponding slotted alloy inserts for the windshield header (the "wheels" at the ends of the L-handles are positioned slightly differently than those at the ends of the motors, so the inserts need to be changed). The kit cost around $600 and I recouped some of the cost by selling my two motors (one good, one bad) on e*ay for around $400. DC Auto's contact info is here: http://dcauto.gotdns.com/questions/new (no affiliation). My mechanic charged me for a few hours of work to replace the motors and the slotted inserts. Unless you're a very good mechanic, I wouldn't try to do it yourself as it's very tricky taking apart the convertible top header panel without damaging it, removing the motors and getting the L-handles aligned properly.

My mechanic also removed the convertible top error light bulb from the clock, as that will be "on" due to the motors being missing from the convertible top header panel. Even without the bulb, you will still need to turn off the "!" warning light in the speedometer using the button on the center console each time you start the car, since the lack of the motors trip the convertible top error warning. That's a bit of an annoyance, but nowhere near as bad as worrying about whether the convertible top header panel is going to bind and fail to close every time I put the top up.

At the suggestion of someone on Pelican Parts, I also bought these "rosettes", which plug into the convertible top header panel around the shafts for the L-handles, giving the header panel a nice "factory" look with the L-handles fitted. See: http://www.ebay.com.my/itm/Rosette-P...item565a4f952d (also no affiliation with the seller). The L-handles are Porsche factory parts that have a "grained" plastic texture that, when combined with the rosettes, look absolutely correct in the header panel when installed.

A few months after converting the header motors to manual, I had the dreaded "main beam" b-pillar failure, in which the motors that raise and lower the top get out of synch and cause the main beam on one side of the top mechanism to snap. The part, which is on indefinite backorder to Porsche in Germany, costs over $1,600 new. Fortunately, when my main beam snapped, it didn't damage the fabric of my convertible top. My mechanic, at Rennwerke in Elmsford, NY, was able to arc-weld my broken beam for a small fraction of the cost of replacing it. Nonetheless, at that point, I decided to convert the up/down function to manual by loosening the bolts on the motors. Look in your owner's manual for the procedure.

Best of luck!

John

Assuming the bolts were tightened correctly (lift levers properly located in the slots): i If the open/close motors appear to "disengage" for both sides, then my first thought would be that you have operated the motors too far when locking/unlocking the top. "Too far" allows the gearboxes (quadrant gear) to become unmeshed from the drive pinions - probably nothing broken as such.

"tightened correctly" Oh oh. What does that mean? the operators manual is unclear on how to tighten them back up again so all I did was tighten them with the same 4 turns that the manual said to loosen them. Does the top have to be in a specific position? What do you mean by "levers properly located in the slots"?

Don´t you think adjusting the existing system had been cheaper and cooler for your nervs???
Wish you nice "open trips"

+1....I noticed the same problem with mine so I have been in manual mode and electric locking.

Question for you, are you hearing the motors are the rear trying to run? I'm wondering if you may have run the transmission gear past its stops (See post #20 on this thread). You may want to try using this DIY to reset the top. This procedure is designed for replacing the cables that actuate the top so its starts from a known starting point. I think this should get you going again.

I hope this helps.