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Old 02-25-2003, 06:13 PM
Posts: n/a
Originally posted by sixto
My dad's US 72 300SEL 3.5 does that. Pretty smart. If the doors are open, no one's going to sneak in though an open window.

I don't know why the windows aren't powered all the time. Maybe so something doesn't blow if a switch gets stuck in the up or down position.

91 300SE
87 300SDL
83 300SD
When power windows became more popular back in the Sixtie's, most car companies had the systems wired to operate at all times. Then came horror stories about children injuring themselves while operating power windows in an otherwise unoccupied car. The first remedial step (found on some US luxury cars in the late Sixtie's) was to add an extra momentary-on switch to the driver's control panel that governed power to the switches when the engine was off. After awhile, that extra feature went away, leaving zero power to the windows when the ignition switch is in the "off" position. Now thanks to the use of a few relays, many cars have a system in which power remains available to the window controls for a limited time, or until the driver's door is opened, whichever comes first.

All this is in my upcoming book "A History of American Power Windows 1937-80" soon to be found on Amazon.
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