OPERATOR'S MANUAL

Preventive Maintenance Electrical System
Medium Duty
(R05/09) Y53-6027 – 227 –
5. After charging, turn OFF charger and disconnect charger
cables.
Bulb Replacement
Tail Lights
To replace the tail lamps, remove lens. The bulbs are all of
the bayonet type.
1. To remove the bulbs, turn bayonet counter clockwise and
pull out.
2. To install, fit the bulb in the socket, push in and turn bay-
onet clockwise.
Replacement Bulbs
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 250 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.
DESCRIPTION PART NO.
Headlights 9007BULB
Front turn signal 3157K LL BULB
Marker 1895BULB
Stop/tail turn 1157BULB
Backup 1156BULB
Hood marker 4157NAK LL BULB
Roof marker 194BULB
Dome 1141BULB
Warning lamp module
#37 or 73 (T1 3/4 wedge base