Mine is a '97 so not sure if yours will be the same or not, but mine is located on the end of the gear shift lever; there's a little button right on the very end, and you push it in once to turn the OD off, push it again to turn it back on.
its in the trunk
It's located on the steering column 2 screws unplug the harnest
The 1999 Mercury Grand Marquis air suspension relay switch can be found on the firewall in the engine compartment. The air suspension relay switch will be on the passenger side of the firewall.
where the starter located on a 1997 grand marquis
On my 1998 Grand Marquis, the fuel shutoff swith is located on the left sidewall of the trunk. Push the button to reset.
on a 1997 Mercury Grand Marquis kill switch be activated by a rear end collision
According to the 2002 Mercury Grand Marquis Owner Guide : The ON / OFF rocker switch for the rear air suspension is located : ( in the trunk , on the drivers side of the trunk , the Owner Guide shows that there is a label next to the switch )
In the trunk
There isn't a reset switch on a 1983 grand marquis as Ford didn't put fuel injection into cars until 1986.
Transmission
Yes. The inertia switch is located in the trunk on the drivers side (up near the trunk hinge) There will be a small white button to reset it.
in my 91 it is in the trunk on the left trunk hinge it is a red button just push it.