TM 5-3805-291-23-1
ELECTRICAL SYSTEM TESTS, INSPECTIONS, AND ADJUSTMENTS - CONTINUED
0013 00
ELECTRICAL POWER SUPPLY CIRCUIT TEST - CONTINUED
2.
Check battery voltage at ECM.
a.
Place battery disconnect switch in OFF position (TM 5-3805-291-10).
b.
Disconnect J1/P1 ECM connector.
c.
Place battery disconnect switch in ON position (TM 5-3805-291-10).
d.
Measure voltage between P1-48 and P1-61.
e.
Measure voltage between P1-52 and P1-63.
f.
Measure voltage between P1-53 and P1-65.
g.
Measure voltage between P1-70 and P1-63.
Expected Results. Measured voltage is between 22 VDC and 27 VDC.
h.
(1)
If results are OK, ECM is receiving correct voltage.
(2)
If results are not OK:
(a) Unswitched power out of range - voltage is not correct for one unswitched battery circuit at ECM.
Proceed to step 3.
(b) Engine start switch voltage out of range - voltage is not correct for engine start switch circuit at ECM.
Proceed to step 4.
3.
Check batteries.
a.
Measure no-load battery voltage at battery posts.
Load test batteries. Refer to TM 9-6140-200-14, Operator's, Unit and Direct Support and General Maintenance
b.
Manual for Lead-Acid Storage Batteries to test battery.
Expected Results. Batteries pass load test. Measured voltage is minimum specification for 24V system.
c.
(1)
If results are OK, batteries are OK.
(a) There is open circuit or excessive resistance in wiring or connections between batteries and ECM.
Verify 15-Amp circuit breaker for ECM is not tripped (TM 5-3805-291-10).
(b) Verify connection at engine ground stud is clean and tight.
(c) Verify battery disconnect switch is functioning properly (TM 5-3805-291-10). Replace as necessary
(WP 0098 00).
(d) Replace wiring harness in question (WP 0195 00 thru WP 0201 00). Ensure seals are properly in place
and connectors are securely connected. Verify repair eliminates problem.
(2)
If results are not OK, battery voltage is low or battery did not pass load test. Recharge or replace faulty bat-
teries (WP 0096 00). Verify repair eliminates problem.
4.
Check voltage from engine start switch to ECM.
a.
Place battery disconnect switch in OFF position (TM 5-3805-291-10).
b.
Remove wire from terminal R of engine start switch (WP 0055 00).
c.
Place battery disconnect switch in ON position (TM 5-3805-291-10).
d.
Turn engine start switch to ON position (TM 5-3805-291-10).
e.
Measure voltage on terminal B of engine start switch to engine ground.
f.
Measure voltage on terminal R of engine start switch to engine ground.
g.
Place battery disconnect switch in OFF position (TM 5-3805-291-10).
0013 00-20
