Ford 2009 F-250 Owner's Manual page 344

Roadside Emergencies
4. Check all battery terminals and remove any excessive corrosion before
you attach the battery cables. Ensure that vent caps are tight and level.
5. Turn the heater fan on in both vehicles to protect from any electrical
surges. Turn all other accessories off.
Connecting the jumper cables
1. Connect the positive (+) jumper 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.
344
2009 F-250/350/450/550 (f23)
Owners Guide, 2nd Printing
USA (fus)