Top intermittent

[Bigal27]

February 2010 purchased my first Porche, Boxster 2.5 auto 1999. Everything fine until a couple of weeks ago then all of the sudden the roof wouldn't go down. If you released the centre latch the windows dropped as per normal but when you pressed the roof button nothing happened and no noises etc, After couple of minute of engine off, engine on, messing with latch, doors opened and closed etc etc all of a sudden the roof worked and was OK. Next time I went to do it the same thing again. Its been the same story now everytime I go to it but yesterday no amount of messing around would get it to work and I gave up after 10 minutes due to lck of time. I have noticed though that the edge of the clam shell loos like it has dropped quarter of an inch where it curles around towards the door on one side, don't know if this is relevant. Another little thing that started to happen is when you put the roof up it would stop a fraction to soon so that when you go to shut the latch it wouldn't locate in the catch with micro switches, had to manually pull it forward, but last couple of times this has been OK. I am in United Kingdom and the Porsche dealers here like to relieve of a couple hundred pounds just to even look at your car!

Has anyone had similar problems?

Where do I start? - Micro switch for window OK as is the handbrake sensor.

[1schoir]

February 2010 purchased my first Porche, Boxster 2.5 auto 1999. Everything fine until a couple of weeks ago then all of the sudden the roof wouldn't go down. If you released the centre latch the windows dropped as per normal but when you pressed the roof button nothing happened and no noises etc, After couple of minute of engine off, engine on, messing with latch, doors opened and closed etc etc all of a sudden the roof worked and was OK. Next time I went to do it the same thing again. Its been the same story now everytime I go to it but yesterday no amount of messing around would get it to work and I gave up after 10 minutes due to lck of time. I have noticed though that the edge of the clam shell loos like it has dropped quarter of an inch where it curles around towards the door on one side, don't know if this is relevant. Another little thing that started to happen is when you put the roof up it would stop a fraction to soon so that when you go to shut the latch it wouldn't locate in the catch with micro switches, had to manually pull it forward, but last couple of times this has been OK. I am in United Kingdom and the Porsche dealers here like to relieve of a couple hundred pounds just to even look at your car!

Has anyone had similar problems?

Where do I start? - Micro switch for window OK as is the handbrake sensor.

Al:

The intermittent operation of your top is not likely caused by either the B-Pillar microswitch or the Clamshell microswitch (present only on '97 to '99 Boxsters), although any of the components/switches/relays are a possibility if there is a loose or corroded connection in any one of the components.

The most likely suspect is one of the two microswitches that are located in the latch receptacle in the windshield frame, with a distant second possibility being a dead spot on the electric motor.

There are two microswitches in the latch receptacle assembly. There is one on the left side of the assembly (has a large plunger that juts out when the latch is open). That one controls the 4" window drop that occurs immediately when you pull down the latch to open the top. There is another one on the right side of the assembly, and that is the one that activates the convertible top double relay.

My guess is that the latter switch is faulty/intermittent, even though it may appear to be intact when you visually inspect it, and sometimes even when you test it with a multimeter. Specifically, take a close look at the solder joints where the leads attach to the plug. This can be hard to detect, so check it with a magnifying glass for hairline cracks in the solder joint and for corrosion. If necessary, heat up the connections with a soldering iron and flow a tiny bit of solder onto the suspect joint(s).

The intermittent nature of the top operation that you described is the main clue. Believe it or not, the temperature (sun light, A/C blowing on it, etc...) can affect it to the point where the connection is broken and then re-established.

To gain access to the microswitch you have to remove the latch plate at the center of the windshield frame. Pop out the two little black plastic "eyes" by carefully prying them off with a very small flat blade screwdriver or borrow one of those "orange sticks" that women use on their fingernails to pry them out. Remove the small torx bolt that you will find under each one of the two eyes. Remove them and then pull down the latch plate carefully until you can see and access the wires for the switch and for the light. Unplug the wires and the latch plate will come off. You will find two fragile retaining clips that attach the switch to the underside of the latch plate. These are easy to break, so use a pair of small needle nose pliers to pull them off, very gently. You can reuse these if you are careful by squeezing the cross sections that are located at the center of the clips until they are flattened.

P.S. DO NOT go to the dealer!

Regards, Maurice.

[grover]

The cab top relay may also be sticking; I can't recall if the window drop signal goes through it or not, though. Know anyone with a known good relay you can swap out to try? It's probably the easiest thing to check, though likely also the most expensive component in the system.

And yeah, you could replace every single part of the mechanism for cheaper than a dealer diagnostic, I think!

Edited July 20, 2010 by grover