It's a safety feature in case something goes wrong, a wire gets shorted, or a switch jambs, etc. Most people would rather have the ability to stop the seat from moving, -than have a crushing experience with their car. Granted the STOP button does make things more difficult when troubleshooting the seats, but I'm glad to have it. I equate it to being able to turn the key off and stop the engine in the rare event that the gas pedal should get stuck down (fortunately most of us aren't bumping the ignition switch as frequently as we bump the STOP button). For clarification, the STOP button is a not a momentary switch. It does have an up/down position, even if it doesn't feel like there's a lot of difference between the two.

Not all problems with the power seats are related to a stuck STOP button, and in many cases the seats are fully functional even though they're not responding to input. If you're unable to get the power seat to move via the switches, make sure you're sitting in the actual seat you want to move, buckle the seatbelt, and then retry the switches. -yet another safety feature! I love these cars.

God bless,
Fitz Fitzgerald.
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'87 Blue 240 Wagon, 253k miles.
'88 Black 780, PRV-6, 146k miles.