Chevrolet Light Duty Truck 1973, Service Manual

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E N G I N E E L E C T R IC A L 6 Y -2 1
1 5 /1 6 ” SOCKET
Fig. 4C—Pulley Removal
Double Groove Pulley
1. Place a 15/16" socket (with wrench flats on the
drive end or use Adapter J-21501 and a box
wrench) on retaining nut, insert a 5/16" alien
wrench through socket and adapter into hex on
shaft to hold the shaft while removing the nut.
Fig. 5C—Torquing Pulley Nut
2. Remove washer and slide pulley, fan and spacer
from shaft.
3. To install, slide spacer, fan, pulley and washer on
shaft and start the nut.
4. Use the socket and adapter with a torque wrench
and tighten nut to 50 ft. lbs. torque.
D IA G N O S IS
Most charging system troubles show up as a faulty
indicator lamp, an undercharged or an overcharged
battery. Since the battery itself may be defective, it
should be checked first to determine its condition. Also,
in the case of an undercharged battery, check for battery
drain caused by grounds or by accessories being left on.
A basic wiring diagram showing lead connections is
presented in Figure
6
C. The following precautions must
be observed when working on the charging circuit.
Failure to observe these precautions will result in serious
damage to the electrical equipment.
• Do not polarize the generator.
• Do not short across or ground any of the terminals
in the charging circuit except as specifically
instructed in these procedures.
• Never operate the generator with the output
terminal open circuited.
• Make sure the generator and Energizer are of the
same ground polarity.
• When connecting a charger or a booster Energizer
to the vehicle Energizer, connect negative terminal
to negative terminal and positive terminal to
positive terminal.
STATIC CHECK
Before making any electrical checks, visually inspect all
connections, including slip-on connectors, to make sure
they are clean and tight. Inspect all wiring for cracked,
frayed or broken insulation. Be sure generator mounting
bolts are tight and unit is properly grounded. Check for
loose fan belt.
NOTE: In some circuits an ammeter may be
used instead of an indicator lamp. In this
case, the section pertaining to faulty indicator
lamp operation may be omitted from the
trouble shooting procedure.
INDICATOR LAMP CIRCUIT CHECK
Check the indicator lamp for normal operation as shown
below.
If the indicator lamp operates normally, proceed to
"Undercharged Energizer" or "Overcharged Energizer"
section. Otherwise, proceed to either one of the following
three abnormal conditions.
1. Switch Off, Lamp On— In this case, disconnect the
two leads from the generator No. 1 and No. 2
terminals. If the lamp stays on, there is a short
between these two leads. If the lamp goes out,
replace the rectifier bridge as covered in the
Overhaul Manual. This condition will cause an under­
charged Energizer.
2. Switch On, Lamp Off, Engine Stopped—This
condition can be caused by the defects listed in step
1 above, by reversal of the No. 1 and No. 2 leads at
LIGHT DUTY TRUCK SERVICE MANUAL