Ford 1998 Crown Victoria Owner's Manual page 105

JUMP STARTING YOUR VEHICLE
The gases around the battery can explode if exposed to flames,
sparks, or lit cigarettes. An explosion could result in injury or
vehicle damage.
Do not push start your vehicle. You could damage the catalytic
converter.
Batteries contain sulfuric acid which burns skin, eyes, and
clothing.
Preparing your vehicle
Also see the label on the battery.
1. Use only a 12–volt supply to start your vehicle. If you connect your
battery to a 24–volt power supply you can damage your starter,
ignition system and other electrical components.
2. Do not disconnect the battery of the disabled vehicle as this could
damage the vehicle's electrical system.
3. Park the booster vehicle close to the hood of the disabled vehicle
making sure they do not touch. Set the parking brake on both vehicles
and stay clear of the engine cooling fan and other moving parts.
4. Check all battery terminals and remove any excessive corrosion before
you attach the battery cables.
5. Turn the heater fan on in both vehicles to protect any electrical
surges. Turn all other accessories off.
Roadside emergencies
105