the actuator to the upper rear door (Fig. 54).
Turn on the
primary or backup hydraulic system and hold the upper rear door
switch in the UP position.
If the actuator opens the door,
replace the flow control valve. If the actuator does not open
the door, replace the pilot check valve.
Hydraulic Actuator and Components.
You located the hydraulic problem. When you attempted to open and close
the upper rear door using the top and bottom upper rear door switches,
you assumed that both switches failed to open or close the door and
continued to troubleshoot the hydraulic problem. Now assume that one of
the switches operated the door and continue to troubleshoot the
Troubleshoot both the top and bottom upper rear door switches in
the same manner.
o Shut down the hydraulic system, set the MASTER switch to the OFF
position, and disconnect lead 10 from the center switch
connector. Using a multimeter to check for voltage, place the
red probe in lead 10 and ground the black probe (Fig. 55). Set
the MASTER switch to the ON position.
If no voltage is
indicated, lead 10 to the switch is defective and you must notify
If voltage was indicated, set the MASTER
switch to the OFF position, reconnect lead 10 to the switch, and