Alan

Auto down is feature of the later window controller (started in '90). The controller also has auto up on just the drivers window - but this feature is not enabled on USA cars (there is a jumper by the controller that can enable this).

Cars before '90 have a thermal cutout on the motors - you are supposed to just stop pushing the button when the window gets to the top/bottom. If you don't the motor stalls and eventually the thermal cutout activates.

With the later controller - it needs to sense when it is at the fully-up and fully-down positions for the auto modes - so it senses the current increase when the motor stalls. It also has a timeout in auto mode (about twice as long as the usual time to open/close). This sensing is the reason why only one motor runs at a time sequentially on the later controller - makes this sensing easier.

Alan

Randy V

Nice write-up.

I'm in the process of redoing my windows.

Is there a trick to getting the roller wheel into the guide channel?

Seems like the roller doesn't line up with the channel opening, regardless of up/down position.

Also, what type fastener connects the roller to the raising arm?

Hymodyne

are the internals the same for a 16V OB?

9two8

Hi Randy.., You need Porsche part number ( rivet 928 537 91700 )

... and if needed here's the plastic roller number ( roller 928 537 91800 )

Randy V

Thanks!

The new plastic wheel roller came with a metal stud (rivet?).

How does it attach to the lifting arm?

edit: More info here:

https://rennlist.com/forums/928-foru...ler-wheel.html

9two8

The rivet goes through the roller wheel, the large flat head of the rivet holds the roller wheel in position , then pass them both through the lift arm hole , place the arm on a steel surface and then pein the rivet head over with a small ball pein hammer, just enough to hold it to the arm, and at the same time not too tight to allow the wheel to turn freely.( Ensure the roller wheel turns freely after peining it over )

...,

Randy V

Thanks, Ken.