Ford 2004 Focus Owner's Manual page 142

Roadside Emergencies
4. Make the final connection of the negative (-) cable to an exposed
metal part of the stalled vehicle's engine, away from the battery and the
carburetor/fuel injection system. Do not use fuel lines, engine rocker
covers or the intake manifold as grounding points.
Do not connect the end of the second cable to the negative (-)
terminal of the battery to be jumped. A spark may cause an
explosion of the gases that surround the battery.
If your vehicle is equipped with a 2.0L engine (SPI or Zetec),
make the final connection to the specific grounding point as
indicated in the following illustrations.
142
2004 Focus (foc)
Owners Guide (post-2002-fmt)
USA English (fus)