Hummer H1 Service Manual page 799

12-28 Electrical System
Step
1 Perform visual inspection on belt, pulleys and
battery cables. Is everything in normal operating
condition
2 Using a battery load tester, place amp pickup on
the alternator fusable link wire. Start and run
vehicle at 1500 rpm, load the vehicle batteries
with 100 amps for 15 seconds. Does charging sys-
tem produce equivalent amperage.
3 Perform battery check, refer to "battery checking
procedure" in this section. Are batteries in good
condition
4 Using a DVOM set to measure voltage, place the
negative lead on a good engine ground. Probe the
Batt. terminal on the back of the alternator. Is
voltage present?
5 Using a DVOM set to measure resistance, mea-
sure resistance between the alternator case and a
negative battery connection. Is resistance below
specification.
6 Disconnect the positive battery cables, using a
DVOM set to measure resistance, measure resis-
tance between the positive battery connection and
the Batt. terminal. Is resistance below specification.?
7 Does voltage gauge indicate a low charge condi-
tion?
8 Using a DVOM set to measure voltage, and the
pink ignition lead disconnected from the alterna-
tor, place the negative lead on a good engine
ground and the positive lead on the pink ignition
lead. Turn the ignition key to on, is voltage
present?
9 Check for expanded female terminal in engine
harness connector in the alternator ignition feed
connector. Is a faulty connection found?
4-1-00
_______________________________________________________
Alternator Inoperative (No Charge)
Action Value(s) Yes
Go to step 2.
>100 amps Go to step 7.
Go to step 4.
12v Go to step 8.
<.2Ω Go to step 6.
<.2Ω Go to step 8.
Replace gauge
and check oper-
ation.
12v Go to step 9.
Replace female
terminal
®
No
Repair and
recheck system.
go to step 3.
Replace batter-
ies and recheck
charging sys-
tem.
Go to step 5.
Locate and
repair bad
ground connec-
tion.
Inspect/repair
fusible link at
alternator Batt
terminal.
No problem
found at this
time.
Locate and
repair open or
short to ground
in engine igni-
tion feed circuit.
Replace the
alternator