Window Dropping When Opening, The Raising Again When Handle Released -- Both Inside and Outside Handle

[AustinPorscheBill]

Had a prior thread on this, thought I fixed it but apparently not.

 

1998 Boxster 986.

 

When opening the passenger door using either the inside handle or outside handle, the window drops so long as the handle is held, but once either handle is released the window goes back up to the closed door position.

 

Originally, only the outside handle exhibited this temporarily down, then back up when released behavior, so I removed the door panel, found that the outer door handle's microswitch had become disconnected (maybe he window had caught it when lowered as the microswitch wiring was not secured but rather hanging free?), reconnected it and put the door back together.

 

After this repair, both handles started to exhibit this window drop then up on release behavior.

I wasn't as detailed as I usually am in documenting tests/changes I've done, but I do believe that  both handles started behaving properly after a programming sequence -- raising window then holding switch for 20 sec, then doing the same after lowering window -- but then reverted to the window drop then up on release behavior after a few cycles.

 

I also sprayed some silicon lubricant director into the lock actuator, and this also seemed to work for a few cycles before returning to the window drop then up on release behavior.

 

Given that both the inside and outside handle are exhibiting this behavior, I am thinking that it is not the handle microswitches that are the problem but rather the lock actuator itself.

 

However, before I start throwing parts at it, I wanted to see if anyone has had this particular problem or can otherwise tell me what my next steps should be.

 

Thanks in advance for any help.

[Loren]

Try re-training the windows. Hold the button down until the window goes down all the way - then do the same for the up motion.

Do this for each window.

[AustinPorscheBill]

Thanks, tried that several times with no success.

Do you know how to tell whether you have the M535 Anti-Theft (315 mhz) as the actuators are different depending on whether you have that option or not.

[AustinPorscheBill]

Concluded it must be the microswitch in the lock actuator, so next question is how to determine whether I have a 315MHz anti-theft chassis so I get the correct replacement lock actuator.

The Build Label under the hood lists Code 535 (315Mhz option right?), but as I am not the first owner (I'm 3rd) and don't know the history (who knows, maybe it was wrecked and a hood was pulled from another Ocean Blue 986), is there any other way I can tell whether I actually have the 315Mhz anti-theft system?

[Loren]

All US/Canada cars were 315Mhz.

[JFP in PA]

On 3/18/2026 at 6:20 PM, AustinPorscheBill said:

Thanks, tried that several times with no success.

Do you know how to tell whether you have the M535 Anti-Theft (315 mhz) as the actuators are different depending on whether you have that option or not.

A scan of the car with a Porsche specific tool (Durametric, PIWIS) can identify if the M535 anti-theft/immobilizer system (Central Locking Unit or CLU) is present and functioning. Diagnostic tools like Durametric or Porsche System Testers can query the alarm module for error codes, confirming its status. 

 

This system is also located under the driver's seat.

[AustinPorscheBill]

I've had the front driver seat out a couple of times (once, after I bought it as it came with a quarter jammed in the guide rail that I had to get out and the other time to actually replace the seat with a better condition on I picked up at a swap meet) and don't recall there being any box under the driver's seat, but that was a couple of years since the last time I had it out.

Should I be able to "feel" the box if it's there or use my borescope to see it?

[JFP in PA]

Yes.