Preventive Maintenance Electrical System
Medium Duty
(R10/06) Y53-6008 – 191 –
Electrical and Alternator Precautions
Take the following precautions to avoid burning out
alternator diodes:
• Do not start the engine with alternator disconnected
(connections removed) from the circuit.
• Before welding, disconnect all electronic connections to
the vehicle batteries.
• Remove battery power cable and insulate it from the
vehicle. See “
Welding” on page 218 for more informa-
tion.
• Do not run the engine with the batteries disconnected.
• Do not disconnect the battery cables or alternator con-
nection cables with the engine running.
• Never turn the ignition switch to the IGN & START posi-
tion with the engine running.
• When charging the battery (installed in the vehicle) dis-
connect the battery cables.
• Do not reverse the cables of the alternator, starter motor,
or battery.
• Do not polarize the alternator. The alternator should not
be polarized like a generator. To ensure correct polarity,
use a test lamp or a voltmeter.
