TM 5-5420-234-14&P
4-12. UNIT TROUBLESHOOTING (continued).
12. HOOK ARM DOES NOT UNLOAD IN MANUAL MODE (MODEL B ONLY) (continued).
NOTE
The digital controller and the cab control box are not repairable,
therefore, it is necessary to test the digital controller and cab
interface wiring harnesses, switches, solenoids, and other com-
ponents to identify possible faults other than the digital controller
and the digital cab controller.
KNOWN INFO
14.
TEST OPTIONS
Error Code, EC 04.
Continuity Tests.
Is there continuity
Remote control unit OK.
measured at the hook
REASON FOR QUESTION
Remote control cable
arm unload valve
OK.
solenoid?
If there is no continuity
Cab digital control box
at the designated
OK.
positions on the hook
Cab interface wiring
arm unload valve
harness OK.
solenoid, the 24 volt
Digital controller wiring
power from the digital
harness OK.
control box does not
activate the hook arm
POSSIBLE PROBLEMS
unload valve.
Hook arm unload valve
solenoid faulty.
Digital control box faulty.
Repair or replace
hook arm unload
NO
valve (para 5-25).
YES
If all previous
tests were
completed with a
satifactory result,
replace digital
control box (para
4-242.6
4- 36
Change 1
