Mercury 2009 Grand Marquis Owner's Manual page 199

Roadside Emergencies
Removing the jumper cables
Remove the jumper cables in the reverse order that they were
connected.
1. Remove the jumper cable from the ground metal surface.
Note: In the illustrations, lightning bolts are used to designate the
assisting (boosting) battery.
2. Remove the jumper cable on the negative (-) connection of the
booster vehicle's battery.
199
2009 Grand Marquis (grn)
Owners Guide, 1st Printing
USA (fus)