Ford 1999 Wagon-Econoline Owner's Manual page 140

Roadside emergencies
Connecting the jumper cables
1. Connect the positive (+) booster cable to the positive (+) terminal of
the discharged battery.
Note: In the illustrations, lightning bolts are used to designate the
assisting (boosting) battery.
2. Connect the other end of the positive (+) cable to the positive (+)
terminal of the assisting battery.
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