TM 5-5420-280-23&P
0008 00
Electrical System Troubleshooting (Contd).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
25. RCU WILL NOT RAISE SUPPORTING CYLINDERS (L21-H+M)
NOTE
KY1 and KY9 driver's side (left) control valve solenoids raise left
side-supporting cylinder and KY1 and KY11 passenger's side
(right) control valve solenoids raise the right side-supporting
cylinder.
Step 1. Check that KY1 and either KY9 or KY11 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 out when action button 1
and 2 are 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. 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 9 for KY9 control valve solenoid, and KL-1 buss bar pin 11
for KY11 control valve solenoid. Refer to Electrical System Schematic (WP 0122 00) and
repair or replace wires (WP 0053 00).
d. Check wire between KL-1 buss bar pin 1 and IQAN-XS connector pin 20. Replace wire if
damaged. Refer to WP 0053 00.
e. Check wires between KL-1 buss bar pins 9 and 11 and IQAN-XP connector pins 19
and 21. Replace wires if damaged. Refer to WP 0053 00.
END OF TESTING
26. RCU WILL NOT RETRACT BRIDGE CRADLE TO TRAVEL POSITION (L22-H+M)
Step 1. Check that KY1 and KY12 hydraulic control valve solenoid LED lights are lit when action
button 1 is depressed.
a. If lights are lit on control valve solenoids, refer to malfunction 4 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 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. 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 and KL-1 buss bar pin 12 for KY12 control valve solenoid. Refer to Electrical
System Schematic (WP 0122 00) and repair or replace wires (WP 0053 00).
d. Check wire between KL-1 buss bar pins 1 and 12 and IQAN-XS connector pins 20 and 36.
Replace wires if damaged. Refer to WP 0053 00.
END OF TESTING
Change 1
