electrical 1997mecury sable station wagon on 1997 Mercury Sable

when i put my 1997 mercury sable in gear the power steering,radio, windows stop working but when i put the car into park in starts working again it started a few weeks ago just in reverse what could this be

Asked by for the 1997 Mercury Sable
Your Sable wagon has a ground problem. When the shifter is in park, there is different gound path than when the shifter is in a forward gear. Most likely one of the main grounds for the devices ( radio, window switches, wipers ) has failed in some way and they are using the shifter as a ground. When you shift in to a gear, there is a less robust ground path and the devices stop working. A good electrical trouble shooting tech needs to trace some wiring. You can start by checking all the fuses on all the fuse panels. As crazy as this probelm sounds, it does happen. You should also look at all of your engine and chassis grounds to make sure they are properly connected and the ground cables are in proper working order. Did anyone do any work on your car recently? Maybe they accidentally forgot to reconnect a body, or engine ground.
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My Sable had the same problem, it was a "transmission position sensor" shorting out. It was around a $100 part plus whatever labor the shop will charge.