Pontiac FIREBIRD 1972 Service Manual page 775

ENGINE ELECTRICAL 6E- 1 3
1. Check fan belt for proper tension (Fig.
A ) as described i n Pontiac Service Manual
Section 6A.
2.
Use a SerCon voltmeter or a similar
one w i t h a wide accurate scale (Fig. B),
and take a voltage reading ( w i t h engine
and all accessories "OFF") between the
t w o battery posts. This voltage is system
battery voltage. Record this reading for
later reference.
NOTE: Battery must be i n good condi-
t i o n t o test charging system (Sec-
tion
12,
Pontiac Service
Manual).
FIG. D
Low or no voltage
-
recheck battery voltage
check voltage between alternator battery
terminal and ground. Check starter sole-
noid (B terminal) for loose or bad connec-
tions
-
check for bad splice in engine har-
ness (splice located i n engine harness on
left side of engine next t o rocker cover
a ~ ~ r o x i m a t e l v 6" from front of enqine).
FIG. A
3.
Ignition switch on, engine and
accessories
( F ; ~ . G.). ~ h e s e three voltage readings
off, check the voltage reading at the No. 1 should be the same.
(brown wire) connection and No. 2 (red
wire) connection at the generator (Fig. C
Low or no voltage at any of these two
and D). Connection may be made w i t h awl
locations indicates bad connection between
or similar instrument as shown i n Fig. D.
that connection and battery.
FIG. B
FIG. E
No.
1
terminal (brown wire) should register
approximately
2
t o 4 volts (Fig. E). N o volt-
age condition open between terminal and
ignition switch
(71
cars w i t h generator
"warning light"
-
check for burned out bulb).
If reading is system battery voltage check for.
short between No. 1 and No. 2 wires.
No. 2 Generator connector (red wire) should
read same as battery voltage recorded i n Step
2
(Fig. F).
FIG. F
Fig. 6E-18
S I
Diagnosis (A)