If the ECV oil is low, the low pressure switch on the engine closes, +24 VDC is applied to engine oil pressure
low A4DS23 indicator on rear control panel which will light (red).
If the ECV coolant system is running hot, the engine coolant switch on the engine closes. +24 VDC is
applied to the engine coolant temperature indicator A4DS22 on rear control panel, which will light (red).
1.15.17 LTG/INTERCOM Circuit Breaker A4CB4.
With LTG/INTERCOM circuit breaker A4CB4 ON, 24 VDC is applied to the following:
a. Left and right map light switches.
Map lights will come on when the appropriate switch (A5DS2S1 or A5DS3S1) is activated.
b. Forward and aft lamps
Forward and aft lamps light when appropriate switches (A18S3 or A7S1) are turned on. Turning on
switches activate the relay which applies 24 VDC power to the lamps.
When DRIVER ALERT button on forward control panel is pressed, 24 VDC is applied to relay A8K1.
Energizing relay A8K1 closes contacts A2 and A3. With contacts A2 and A3 closed, 24 VDC is applied to
DRIVER ALERT indicator A8DS1 on vehicle control box in cab. To acknowledge, the crew in cab presses
DRIVER ACKNOWLEDGE button A8S1. This removes the 24 VDC from indicator.
When the crew in cab presses SHELTER ALERT button A8S2, 24 VDC is applied to shelter buzzer A5S1 on
forward control panel. To acknowledge and reset buzzer, the crew in LMS presses SHELTER
ACKNOWLEDGE button A5S2.
During INTERNAL operation, the ECV engine must run faster than normal idle speed to turn primary
hydraulic pump fast enough to produce adequate hydraulic fluid flow to operate CBPS hydraulic
components. The CBPS uses an Electronic Programmable Governor controller to regulate engine speed at a
high idle of 1400 - 1500 RPM. Actual engine high idle speed is the RPM required to produce sufficient
hydraulic fluid flow to operate NBC FAN at correct speed for NBC operation.
With the ECV transmission shifter positioned to NEUTRAL or PARK and EPG switch A8S3 positioned to
"ON", 24 VDC is applied to EPG controller to activate automatic regulation of EPG linkage assembly
position. A magnetic pick-up speed sensor senses ECV engine speed which is converted to an electrical
signal and input to EPG controller.
1.16.1 General. The engine driven pump supplies high pressure fluid
to the hydraulic manifold
in the ECU,
and from there, fluid is distributed to each of the major components as selected by mode selection. Speeds of
various components are controlled by flow control devices to minimize the impact of variations in engine
speed or other operating components. During periods requiring engine maintenance, external power is
required to power the system, and the hydraulic flow is developed during this mode by an electric motor
driven pump located in the ECV passenger side wheel well. See table 1-1 for a brief explanation of the
function of components listed on the hydraulic schematic.
For maintenance purposes, the solenoid valves located in the ECU have manual overrides (refer to
a manual override for SV1, SV2, SV4 through SV6 and SV8, push button in, twist
counterclockwise 180 and release. In this position, the valve will remain open. To return to normal
operation, push button in, twist clockwise 180 and release. To activate a manual override for SV7 or SV9,
push and hold override button. Activating solenoid valve SV1, SV2, SV4 through SV6, and SV8 override will
open the selected port and cause hydraulic fluid to flow through the port. Activating solenoid valve SV7 and
SV9 override, causes the hydraulic port to close and the fluid to stop.
Solenoid valves SV1, SV2, SV4 through SV6, and SV8 have the same part number and, under certain mal-
functions such as a leaking valve, may be exchanged to rectify the problem. Solenoid valves SV7 and SV9
have different part numbers and should not be exchanged with other solenoid valves even though they look