TM 5-3805-298-23-2
0142
Table 1. Rear Window Defroster Does Not Operate - Continued.
0142
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
4. Using digital multimeter
Rear Window Defroster
Voltage 18 to 28 V Replace upper cab
(WP 0174), test for voltage
Does Not Operate -
wiring harness (WP 0292).
between connector C-C24
Continued
Proceed to Test Step 12.
(WP 0012, Figure 140) terminal 9
Voltage Less Than 18 V Replace
and ground.
lower cab wiring harness (WP 0291).
Proceed to Test Step 12.
Test Step 4. Test for Open Rear
Window DEF Fuse.
1. Turn ignition switch and battery
disconnect switch to OFF position
(TM 5-3805-298-10).
2. Remove rear window DEF fuse
from fuse panel (TM 5-3805-298-
10).
3. Using digital multimeter
Resistance 5.0 Ohms or Less Install
(WP 0174), measure resistance
rear window DEF fuse (TM 5-3805-298-
between terminals of rear window
10) and proceed to Test Step 5.
DEF fuse.
Resistance Greater Than 5.0 Ohms
Replace rear window DEF fuse (
TM 5-3805-298-10) and proceed to
Test Step 9.
Test Step 5. Test for Faulty Defroster
Relay.
1. Swap defroster relay (WP 0364)
with front work light relay
(WP 0290).
2. Turn battery disconnect switch and
ignition switch to ON position
(TM 5-3805-298-10).
3. Press rear defrost switch to on
(momentary) (TM 5-3805-298-10).
4. Observe operation of rear defrost
Rear Defrost Switch Indicator Lights
switch indicator (TM 5-3805-298-
Swap defroster relay back to front
10).
work light relay position and replace
defroster relay (WP 0364).
Proceed to Test Step 12.
Rear Defrost Switch Indicator Does
Not Light Proceed to Test Step 6.
0142-3
