Mercury 2009 Grand Marquis Owner's Manual page 186

Roadside Emergencies
WARNING: To reduce risk of electrical shock, always replace
the cover to the Power Distribution Box before reconnecting the
battery or refilling fluid reservoirs.
If the battery has been disconnected and reconnected, refer to the
Battery section of the Maintenance and Specifications chapter.
The high-current fuses are coded as follows.
Fuse/Relay
Location
1
2
3
4
5
6
7
8
186
2009 Grand Marquis (grn)
Owners Guide, 1st Printing
USA (fus)
Fuse Amp Protected Circuits
Rating
30A* Ignition switch
20A* Heated seats, moon roof
10A* Powertrain Control Module (PCM)
keep alive power, Canister vent
20A* Fuel relay feed
10A* Rear Air Suspension Module
(RASM)
15A* Alternator regulator
30A* PCM relay feed
20A* Driver's Door Module (DDM)