VALVE GP-RELIEF 1989219 - Caterpillar

Armrest Position Switch
Note: On machines with left joystick only. Machines with steering wheel does not have an armrest position switch.
Illustration 15 g02282613
Armrest position switch as viewed with the armrest in the raised position
The Armrest Position Switch is located under the left armrest toward the rear of the armrest base.The Armrest Position Switch is used as a machine interlock device. The engine will start with the left armrest in the UP position, however, the Implement ECM will not enable steering operation until the armrest is in the DOWN position.The switch provides two switch-to-ground inputs to the Implement ECM and the Machine ECM. A ground circuit is supplied to the switch by the Implement ECM.When the normally closed input circuit is grounded, the ECM determines that the armrest is in the UP position. When the normally open input is grounded, the ECM determines that the armrest is in the DOWN position.Each ECM expects to detect one switch circuit grounded at all times. If both switch circuits are grounded or if neither switch circuit is grounded, either one or both ECMs could activate a CID 1628 (Armrest Stowed Switch) diagnostic code.Note: If the optional steering wheel is equipped on your machine, the left armrest position switch enabled condition will NOT apply.Steering Operation (Hydraulic)
Illustration 16 g03562423
Steering Hydraulic System (HOLD)
(1) Steering Pump
(2) Steering control valve
(3) Backup relief valve
(4) To brake/fan combination valve
(5) Back pressure valve
(6) Makeup and relief valve
(7) Makeup and relief valve
(8L) Left side steering cylinder
(8R) Right side steering cylinder
(9L) Left secondary (redundant) steering solenoid
(9R) Right secondary (redundant) steering solenoid
(10) Pilot oil from brake/fan combination valve (redundant)
(11) Pilot accumulator
(12) Pilot oil supply from brake/fan combination valve
(13) Steering pilot solenoid
(14L) Left primary steering solenoid
(14R) Right primary steering solenoid
(15) Steering control spoolThe steering pump (1) provides flow to the steering control valve (2). Supply oil will enter the steering control valve and flow to the steering control spool (15).Pump supply oil is blocked when the control spool is in the HOLD position. Oil in the load sense circuit is blocked by the steering cylinders (8L) and (8R), and the pump control valve. Pump supply oil is also sent to