Electrical

Power Window Switch Info

Regarding my sunroof and driver's-side window that stopped working...

Took another look at this problem last night. As it turns out, the problem was caused by a replacement switch that I had installed on the *passenger* side window a week or two ago.

My original passenger side switch was Porsche part number 928.613.123.07. The replacement from 928 International was part number 928.613.123.05 (note the slightly different last digit). These appear to be the same, but there are internal differences that I didn't notice. I should have taken more time to investigate this before installing the replacement.

Anyway, for those of you with my MY (90 S4) or later, take note: the .05 is *not* a drop-in replacement for the .07. Here are the details: the .07 is a simple SPDT switch. Red wire is common. It momentarily loses to green wire for "window up" and momentarily closes to black wire for "window down".

The .05 has four wires: red, green, black, and brown (I assumed brown wasn't used and otherwise the .05 and .07 were equivalent; I was wrong!) On the .05, the behavior with red/black/green is the same as the .07 above *except* there is also continuity across green and black unless "window up" or "window down" is pressed. This all seems rather strange until you open up the switch and look at its inner workings. Anyway, if you open up the .05 switch, you can snip off the part that the brown wire attaches to and effectively turn the .05 switch into a simple SPDT .07 switch.

What's really strange is that due to the continuity across black/green that was appearing on my passenger-side window switch (the .05) when it wasn't activated, it caused both the sunroof and the driver's side window motors to always move in the "close" direction regardless of pressing the "open" or "close" ends of their switches. Bizarre! (although probably understandable if you look at the wiring diagrams).

Anyway, the moral of the story is that there is more than one kind of window switch and they *are not* interchangable. You *can* convert a .05 to a .07 using the "snip off" technique I mentioned above.

For the record (and the archives), here's the difference between the 928.613.123.05 and 928.613.123.07 window switches. The figures will only look right in a monospaced typeface.

.05 operates like this (slash and backslash are moving parts):
: NC=normally closed
: NO=normally opened
:
: [close] [open]
: brn
: |
: o-----|-----o
: NC / \ NC
: blk --o o-- grn
: NO NO
: o-----|-----o
: |
: red
:

.07 operates like this (slash and backslash are moving parts):
: NO=normally opened
:
: [close] [open]
:
: / \
: blk --o o----|----o o-- grn
: NO | NO
: red
:


--
Ed Scherer
'90 928S4