TM 5-3805-298-23-2
0142
Table 1. Rear Window Defroster Does Not Operate.
0142
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
NOTE
Rear Window Defroster
Does Not Operate
Always inspect wiring harness connectors that are involved in the circuit.
Poor connections can often be the cause of a problem in an electrical
circuit. Verify that all connections in the circuit are clean and secure and
that all connections are in good condition. If a problem with the
connection is found, correct the problem and verify that this malfunction
or diagnostic code is active before performing this procedure.
Perform open or short-circuit test at each wiring harness connection to
identify the correct wiring harness to replace.
Tag all wiring harnesses to aid in installation.
Perform this test only if condition is active.
Test Step 1. Test Operation of Rear
Window Defroster.
1. Turn battery disconnect switch and
ignition switch to ON position
(TM 5-3805-298-10).
2. Press rear defrost switch to on
(momentary) (TM 5-3805-298-10).
3. Observe operation of rear defrost
Rear Defrost Switch Indicator Lights
switch indicator (TM 5-3805-298-
Proceed to Test Step 2.
10).
Rear Defrost Switch Indicator Does
Not Light Proceed to Test Step 4.
Test Step 2. Test for Voltage at Rear
Window Defroster.
1. Press rear defrost switch to on
(momentary) (TM 5-3805-298-10).
2. Using digital multimeter
Voltage 18 to 28 V Replace rear
(WP 0174), test for voltage
center glass.
between rear window defroster
Proceed to Test Step 12.
(WP 0012, Figure 207) terminal 1
Voltage Less Than 18 V Proceed to
and terminal 2 (ground).
Test Step 3.
Test Step 3. Test for Voltage at Lower
Cab Wiring Harness.
1. Turn ignition switch and battery
disconnect switch to OFF position
(TM 5-3805-298-10).
2. Disconnect connector G-C3
(WP 0012, Figure 139) from
connector C-C24 (WP 0012,
Figure 140).
3. Turn battery disconnect switch and
ignition switch to ON position
(TM 5-3805-298-10).
