I'm having problems with the electric top on my 993 cab and would really appreciate any tips from the knowledgeable folks on here.

The cab top was working fine and has been pretty good in the 7 years I've owned car although I did have to replace one of the drive cables from the rear motors about 5 years ago.

A couple of weeks ago when I went to open the top the front locking mechanism released the front of the roof but it didn't carry on winding back it just stopped.

So you could unlock or lock the front motors but the roof didn't retract.

I then discovered if you pressed the button and let the front unlock and then lifted the front slightly by hand and carried on pressing the button the roof would open fully.

Shutting roof was as normal so you just pushed the button to close it and the whole thing closed until it dropped onto the top of the windshield and the front locking mechanism would lock it into place.

It worked like this ok for a couple of weeks but yesterday when I try to open the roof only the front motors would unlock and the rest of the roof would not open.

And now it won't lock shut or open at the front at all. It is currently stuck with the front locks undone and the roof just resting on the top of the windscreen surround.

I have checked fuse number 13 for the cab roof and a fuse is good.

I’ve also checked the 2 microswitches at the rear right hand panel and both seem accurately positioned and clicking on/off at the right point (roof open/roof closed). I haven’t tested the switches with a meter though.

I’m keen to know what sensors control the front locks and what the sequence is for opening and firing up the various motors.

Any thoughts or checks I can do gratefully received.

 

Check these two web links out. One addresses how to adjust the cable (the drive cables maybe need a slight adjustment). The other video discusses how to replace the gear in the latch motor (tooth on brass gear fractures-easy fix).
Here:
https://p-car.com/diy/cabtop/

https://youtu.be/VMnGfM3I-Xw

When I had my cab a few years ago it ultimately ended up being the control board. I had a local professional re-flow the board and it worked perfect after that. These are getting up there in age and can just start to crack. Being a RHD likely living in the UK you're in luck sir! It is WAY easier to remove than LHD cars! Test your micro switches too. There are a couple under that panel too where the motors are along the front bow-where it meets the windshield frame.
Hope that helps.

 

[QUOTE=a993lad;16598560]I'm having problems with the electric top on my 993 cab and would really appreciate any tips from the knowledgeable folks on here.

The cab top was working fine and has been pretty good in the 7 years I've owned car although I did have to replace one of the drive cables from the rear motors about 5 years ago.

A couple of weeks ago when I went to open the top the front locking mechanism released the front of the roof but it didn't carry on winding back it just stopped.

So you could unlock or lock the front motors but the roof didn't retract.

I then discovered if you pressed the button and let the front unlock and then lifted the front slightly by hand and carried on pressing the button the roof would open fully.

Shutting roof was as normal so you just pushed the button to close it and the whole thing closed until it dropped onto the top of the windshield and the front locking mechanism would lock it into place.

It worked like this ok for a couple of weeks but yesterday when I try to open the roof only the front motors would unlock and the rest of the roof would not open.

And now it won't lock shut or open at the front at all. It is currently stuck with the front locks undone and the roof just resting on the top of the windscreen surround.

I have checked fuse number 13 for the cab roof and a fuse is good.

I’ve also checked the 2 microswitches at the rear right hand panel and both seem accurately positioned and clicking on/off at the right point (roof open/roof closed). I haven’t tested the switches with a meter though.

I’m keen to know what sensors control the front locks and what the sequence is for opening and firing up the various motors.

Any thoughts or checks I can do gratefully received.[/QUOTEI

I have owned my cabriolet since new. My experience has/is to take your car to a mechanic who specializes working on Porsche convertible tops.
The drive cables must be perfectly synchronized with the motors. If all of the moving parts aren't synchronized perfectly, you can damage your convertible top frame and your top.
Also, always replace both drive cables and only use Genuine Porsche drive cables.
Your mechanic must have experience in Porsche convertible tops.
Based on your description, this not a do it yourself job.
In the interim, convert your top to manual operation in order to lock your top closed. You will need to loosen both bolts near your rear speakers not greater than one (1) turn each side. Close your top manually and latch each side (above the windshield) with the tool provided with your car.
If your near Philly, I can recommend a mechanic.
If you're not near Philly, other members may recommend a mechanic in your area.
This is not a job for a Porsche convertible top installer or a Porsche upolsterer.
I hope this information proves helpful.
Keep us informed.

 

Hi folks

thanks for the replies so far which are much appreciated

I have a bit more information as I've now done a bit more investigating.

So I was starting from a situation where the roof was unlocked at the front but sitting on the windscreen surround but the button would neither open it further nor lock it shut.

I removed the cover from the front locking latches and tested the two microswitches next to the locking Motors and both seem to function correctly. Ie they click when you move the front of the roof up or down a little. I didn't actually test with a meter.

the roof would still not lock down at the front so I locked it down manually using the tool in the car tool kit for turning the motors by hand. once the roof was locked down at the front I then tried opening it using the usual electric button. And it opened fully all the way.

but when I closed it using the button it closed up to the point where the roof dropped down onto the top of the windshield but the the front locks don't operate.

any thoughts on why the motors for the front locks open normally but will not close and lock the roof down?

 

the micro switches might be messed up.
check the two in the gears, side panel behind passenger seat.

 

So A quick update on this as I am still messing about with my cab roof and it is proving quite frustrating but I'm sure it must be fixable.

Having tested just about everything in the system I think my problem lies with the micro switches on the front of the roof and the timing for when they are on or off.

The switches themselves work fine and mechanically seem in good condition. But the problem seems to be That the roof does not raise itself high enough at the front when the two front locks release from their catches.

Both of the front microswitches need to go off in order for the motor at the rear To fire up. But when my catches release at the front the roof doesn't raise very high and if I set the microswitches to be off at that point Sometimes the motor at the back starts running before one of the catches has fully released which is obviously not a good thing.

If I move the microswitches forward a tiny amount to make sure that they don't go off until the catch is fully released at the front the motor at the back then doesn't fire up because the microswitches are still in the off position even though the roof is open at the front.

So I can make the roof operate completely by pressing the button And then as soon as the catches have fully released at the front I need to immediately lift the roof up slightly so the 2 microswitches at the front go to the off position and then the motor fires at the back and the roof retracts normally to the fully open position.

It really does just seem like the roof sits too low after the catches have released for the front microswitches to operate effectively.

Any thoughts from people have seen this before or Can tell me how high the front of the roof should be after the catches have released before the motor kicks in would be gratefully received

 

Had the same problem, back motors would not work and sometimes the front latches did not work. I made the top manual and replaced the latch motors.