Ford 1999 Wagon-Econoline Owner's Manual page 162

Maintenance and care
Gasoline engines
Disconnect:
1. Disconnect the primary battery
ground cable.
2. Disconnect the auxiliary battery
frame ground.
• Remove the ground bolt.
• Pull the cable away from the
frame and make sure that the
cable does not contact the frame.
Connect:
1. Reconnect the auxiliary battery
frame ground.
162