HOUSING AS-REGULATOR 7E6466 - Caterpillar

Note: Abbreviated EID description is what will appear on Advisor/Info Display along with abbreviated action text to suggest the appropriate corrective action.Pin Identification
Table 3
Pin ECM Function 990/844 T4 PPRD 993 T4 BU 992/854 T4 BU 994H (Reference)
J2–9 300mA SINK DR 1 Powered Stairway Disable Relay Powered Access Disable Relay Powered Access Disable Relay Powered Access Disable Relay
J2–31 SWG 18 Powered Access Position Switch ( Normally Open) Powered Access Position Switch Powered Access Position Switch ( Normally Open) Powered Access Position Switch (Normally Open)
J2–59 SWG 32 Active Analog 2 Powered Access Position Switch (Normally Closed) Stairway Movement
Control Switch
The control switch will power wire 745-GY(Grey)with 24VDC in either the up or down direction. The wire 744-BU(Blue)will only be powered with 24VDC in the down direction.Actuator Controller
With the actuator fully extended "Pin #4" on "450–1625" Control Out #1 should be 24VDC. "Pin #2" should be ground.With the actuator fully retracted "Pin #2" on "450–1625" Control Out #1 should be 24VDC. "Pin #4" should be groundIf the actuator is not fully retracted or extended, both "Pin #2" and "Pin #4" should be ground."Pin #3" and "Pin #1" should always have 24VDC to supply power to the control circuit in the controller.The direction of the actuator is controlled by R840-BU(Blue)and R841-GN(Green).
WhenR840-BU(Blue)has positive voltage, the actuator will extend.
WhenR841-GN(Green)has positive voltage, the actuator will Retract.Latch System
Unlatching
Unlatching the system starts with the control switch pressing down to lower the ladder. Wire 744-BU(Blue)will power wire R841-GN(Green)to 24VDC through the ladder lower relay. Wire R840-BU(Blue)will be ground through the ladder raise relay. Once the actuator has moved from the fully extended position, "Pin #4" on the controller will no longer have 24VDC and will turn on the powered access stairway alarm in the box.Latching
Latching the system starts with the control switch pressed up to lower the ladder. This will power wire 843-YL(Yellow)through relay Switch Signal Conversion. Once the ladder is raised enough to activate the proximity sensor at the top of the box wire E788-BU(Blue)will go to ground and activate Actuator Latch Relay. The Actuator Latch Relay will connect wire L920-BR(Brown)to 144-RD(Red)to24VDC power. This will send R840-BU(Blue)to 24VDC and R841-GN(Green)to ground through the Ladder Lower relay. The actuator will begin to extend until reaching the fully extended position and the switch is held. Once fully extended the alarm in the box will turn off and the latch will no longer extend any further.Alarm System
Box Alarm
The box alarm in the powered access will be active anytime the stairway directional control is actuated and the latch is not fully extended. Alarm will continue to sound when the ladder is moving in either direction and will shut off once the ladder is fully raised and the latching pin is fully extended.Cab Alarm
The cab alarm is linked to the actuator and controller through "Pin #4" Connection Control Out #1 on the actuator controller. When 24VDC is present across "Pin #1" and "Pin #4" of the actuator controller, the Latched Position relay will drive the M904-OR(Orange)wire to ground. WhenM904-OR(Orange)is not grounded a