TM 5-5420-280-23&P
0008 00
Electrical System Troubleshooting (Contd).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
5. RCU WILL NOT RETRACT WINCH WIRE ROPE (L3-A) (Contd)
Step 6. Check to see if one or more control valve solenoid LED lights are out when action button 1
is depressed.
a. If light is out, check for 24 volts at control valve solenoid.
b. If connector has 24 volts, replace control valve solenoid or hydraulic control valve
c. If connector has no voltage, check wires at KL-1 buss bar pin 1 for KY1 control valve
solenoid, KL-1 buss bar pin 21 for KY21 control valve solenoid, and KL-1 buss bar pin 29
for KA5 limit switch. Refer to Electrical System Schematic (WP 0122 00) and repair or
replace wires (WP 0053 00).
d. Check wires between buss bar KL-1 pins 1 and 21 on IQAN-XS connector pins 20 and 36
and buss bar KL-1 pin 3 and IQAN-XP connector pin 37. Replace wires if damaged
e. Check wires between KL-1 buss bar pin 29 and IQAN-XP connector pin 17. Replace wire
if damaged. Refer to WP 0053 00.
END OF TESTING
6. RCU WILL NOT EXTEND SUPPORTING CYLINDERS (L4-A+M) OR (L7-A)
NOTE
KY1 and KY8 driver's side (left) control valve solenoids extend left
side-supporting cylinder, and KY1 and KY10 passenger's side
(right) control valve solenoids extend the right side-supporting
cylinder.
Step 1. Check that KY1 and either KY8 left or KY10 right hydraulic control valve solenoid LED
lights are lit when action button 1 or 2 is depressed.
a. If both lights are lit on control valve solenoids. Refer to malfunction 3 in Hydraulic
System Troubleshooting, WP 0010 00.
b. Check operation of IQAN-XP and IQAN-XS LED lights. Refer to WP 0004 00 step h.
Step 2. Check to see if one or more control valve solenoid LED lights are lit.
a. If only one light is lit, check for 24 volts at control valve solenoid without a light.
b. If connector has 24 volts, replace control valve solenoid or hydraulic control valve. Refer
to WP 0075 00.
c. If connector has no voltage, check wires at KL-1 buss bar pin 1 for KY1 control valve
solenoid, KL-1 buss bar pin 8 for KY8 control valve solenoid, and KL-1 buss bar pin 10
for KY10 control valve solenoid. Refer to Electrical System Schematic (WP 0122 00) and
repair or replace wires (WP 0053 00).
d. Check wires between KL-1 buss bar pin 1, pin 8, or pin10 and IQAN-XS connector pin 20,
IQAN-XP connector pins 18 or 20. Replace wires if damaged. Refer to WP 0053 00.
END OF TESTING
Change 1