On a 1996 Mercury Sable : The thread on cap on the engine coolant reservoir is the pressure cap / radiator cap
It is located where the upper radiator hose connects to the engine.
The 1996 Mercury Sable the OBD 2 connector is under drivers dash next to kick panel
( fuse # 21 ) is a 20 amp fuse for the cigarette lighter on a 1996 Mercury Sable
Check the fuse
It was the starter
On a Mercury Sable : firewall 1-----2-----3 4-----5-----6 front of vehicle > driver
I suspect the process for removing a radiator from a 1996-1999 Sable is very similar to the 2001 - so the instructions in the "Related Question" below should be an excellent start.NOTE: please come back and edit this question and ADD your own experiences and findings!