TM 5-3805-290-23-1
TROUBLESHOOTING WITHOUT A DIAGNOSTIC CODE - CONTINUED
0008 00
Table 2. Electrical System Troubleshooting - Continued.
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
3. Check defroster switch.
1. If machine ECM indicates defroster
16. Rear Defroster is
(a) Battery disconnect switch and
switch status changed when switch was
Inoperative or Always On -
engine start switch remain in ON
unplugged or grounded, replace
Continued.
position (TM 5-3805-290-10).
defroster switch (WP 0049 00).
(b) Disconnect wiring harness from
2. If machine ECM indicates defroster
defroster switch (WP 0049 00)
switch status did not change when
while monitoring defroster switch
switch was unplugged or grounded,
status on MSD.
there is an open circuit or short to
(c) Use a jumper wire to momentarily
ground between machine ECM and
ground defroster switch wiring
defroster switch. Replace wiring
harness pin 3, circuit 504 (GN)
harness in question (WP 0169 00 thru
while monitoring defroster switch
WP 0175 00).
status on MSD.
4. Check ECM.
1. If defroster operated when ECM
(a) Disconnect machine ECM
harness was grounded, replace
connector J2 (WP 0052 00).
machine ECM (WP 0052 00).
(b) Battery disconnect switch and
2. If defroster did not operate when ECM
engine start switch remain in ON
harness was grounded, remove all
position (TM 5-3805-290-10).
jumpers, reconnect all wiring
(c) Use a jumper wire to ground
harnesses, and temporarily replace
machine ECM wiring harness J2-
defroster relay (WP 0054 00). If
13, circuit 507 (YL).
problem still exists, reinstall old relay
and go to Test 5.
5. Check power to defroster relay.
1. If battery voltage is present at both
(a) Remove defroster relay (WP 0054
pins, go to Test 6.
00).
2. If battery voltage is not present at both
(b) Turn battery disconnect switch
pins, there is an open circuit between
and engine start switch to ON
defroster relay and defroster fuse.
position (TM 5-3805-290-10).
Replace wiring harness in question
(c) Measure voltage at defroster relay
(WP 0169 00 thru WP 0175 00).
between wiring harness pin 1,
circuit 140 (BU), and ground; and
between wiring harness pin 2,
circuit 140 (BU), and ground.
6. Check circuit to defroster grid.
1. If continuity is present, go to Test 7.
(a) Defroster relay remains removed. 2. If continuity is not present, there is an
(b) Disconnect wiring harness from
open circuit between defroster relay
defroster switch (WP 0049 00).
and defroster grid. Replace wiring
(c) Turn battery disconnect switch
harness in question (WP 0169 00 thru
and engine start switch to OFF
WP 0175 00).
position (TM 5-3805-290-10).
(d) Check continuity at defroster relay
between wiring harness pin 4,
circuit 538 (OR), and defroster
grid.
0008 00-39
