Left Heated Windshield Inoperative - Hummer H1 Service Manual

12-90 Electrical System
Step
1 Gain access to the heated windshield connections.
With the ignition in the "RUN" position, preform a
voltage drop test between the yellow wire (CKT 740)
and the black wire (CKT 59) going to the left hand
windshield. Turn the heated windshield "ON". Is the
specified voltage present?
2 Using a DVOM check the resistance to ground at
the black wire (CKT 59) going to the left side
windshield. Does the resistance to ground meet
the specified range?
3 Remove the left hand heated windshield relay from
the exterior fuse box. Check the voltage drop
between cavities 1 (CKT 580) and 2 (CKT 59). With
the ignition in the run position, turn the heated wind-
shield switch to "ON". Is the specified voltage
present?
4 With the ignition still in the run position. Preform
a voltage drop test between cavities 2 (CKT 59)
and 3 (CKT 738). Is the specified voltage present?
5 With a DVOM check the resistance between cav-
ity 5 (CKT 740) and the yellow wire (CKT 740)
going to the left side windshield. Does the resis-
tance meet the specified value?
4-1-00
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Left Heated Windshield Inoperative

Action Value(s) Yes
12v Replace the
heated
windshield.
<.2 Ω
Go to step 3.
12v Go to step 4.
12v Go to step 5.
<.2 Ω
Replace relay
R-4.
®
No
Go to step 2.
Repair the open
or bad connection
in CKT 59
between the
windshield and
G4.
Repair the open
or bad connec-
tion in CKT 580
between the
heated wind-
shield switch
and Heated
windshield relay
(R-4).
Repair the open
or bad connection
in CKT 738
between fuse 2C
and R-4.
Repair the open
or bad connection
in CKT 740
between the left
side heated wind-
shield and R-4.