https://www.truck-manuals.net/mack/ 248 MAINTENANCE AND LUBRICATION BATTERY
CAUTION To avoid damage to sensitive electronic equipment, disconnect ALL battery cables and harnesses to electronic control units before welding. Do NOT disconnect batteries while engine is running.
Jump-Starting Engine If you encounter a situation in which it is necessary to jump-start an engine, use the following procedures.
WARNING Batteries which are to be linked together must be of the same voltage (12 to 12, 24 to 24). Take care to observe proper polarity when connecting batteries. Batteries produce explosive gases. Keep sparks, flames, cigarettes, etc., away from batteries at all times. Protect your eyes by wearing safety goggles. Be sure vehicles are NOT touching each other.
CAUTION To avoid damaging any electronic controllers when jump-starting a V-MAC vehicle, always turn the ignition switch OFF before connecting the batteries. 1. Connect the positive (+) cable to positive (+) post of discharged battery or to the positive post of the remote jump-start connector (if equipped). 2. Connect the other end of the same cable to the positive (+) post of the booster battery. 3. Connect the second cable, negative (-) side, to the other post of the booster battery. 4. Make the final connection to the negative (-) battery terminal or the remote jump-start connector (if equipped) of the stalled vehicle, and stand back. 5. Start the vehicle with the booster batteries and then start the stalled vehicle. Shut down the vehicle with the booster batteries and remove the cables in the reverse order of connection.
