Depends on what's wrong with the door.
It's the upper strut bushings. It probably will gwt worse when it's cold.
The 1995 Mercury Sable would have come from the factory with ( 5W-30 ) oil in the engines
Probably , there would be a fuse box in the passenger compartment and a Power Distribution Box ( which is " live " ) located in the engine compartment
If you DIY it will cost around $175. If you pay someone to do it expect to pay around $500. This is a labour intensive repair.
It would probably be cheaper to replace the cable, check with your local auto wrecker. This used part should be very inexpensive, compared to repairing it.
Could be a bad inertia switch.
how much would it cost on a 2004 mercury sable
On a 2000 Mercury Sable : The automatic transaxle ( transmission ) fluid level dipstick would be near the firewall just to the drivers side of the engine ( where the transaxle is bolted to the engine )
Replace your transmission pump or get a new transmission.
According to the 2002 Mercury Sable Owner Guide : ( the 6 disc C.D. changer is either located in the center console , the trunk , or the right side of the cargo area , that would be for the wagon version )
Do one side at a time so you have one complete one for reference. If you're not familiar with brakes I would recommend purchasing a repair manual for that vehicle. It will save you time and money.
check all your ground wires