Ford 2005 F250 Owner's Manual page 230

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.
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