CYLINDER & SEAL GP-BOOM 1184069 - Caterpillar

In normal operation, the switches for the direction lever close the direction inputs on the ECM to ground. The closed switches tell the ECM the direction that is selected by the operator. The ECM then activates the appropriate directional solenoid.Note: Because two input lines are used for each direction, the ECM can diagnose problems with the circuits for the direction lever. A solenoid for direction is not activated and the transmission remains in neutral if the following actions occur:
The direction lever does not ground either of the forward inputs or reverse inputs of the ECM.
The direction lever grounds both the reverse input and the forward input at the same time.Neutralizer Switch
Illustration 5 g00730228
Neutralizer switchThe neutralizer switch is a two-position switch that is a limit switch and the neutralizer switch is located inside the assembly of the brake pedal valve. The switch is closed to ground when the brake pedal is depressed. The switch is open when the brake pedal is released.The neutralizer switch is activated when the brake pedal is depressed. This closes the neutralizer input line. The solenoids for direction are not activated and the speed clutch remains activated when the transmission is neutralized.Note: The neutralizer switch is wired in series with the neutralizer override switch.Pressure Switches For The Neutralizer
Illustration 6 g00735416
Pressure switch for the neutralizerThe neutralizer function consists of two pressure switches (80 psi and 220 psi). Both of the switches are open when the service brake pedal is released. This allows the transmission to be placed in gear according to the position of the shift lever, the position of the auto/manual switch, and machine speed.When the 80 psi switch closes, the transmission is neutralized by de-energizing the direction clutch. The transmission remains neutralized until the 80 psi switch opens or until the 220 psi switch closes. If the 80 psi switch opens, the transmission is placed back into gear. If the 220 psi switch closes, the transmission will remain neutralized until the 220 psi switch opens. The transmission is placed back into gear when the 220 psi switch opens.Neutralizer Override Switch
Illustration 7 g00726604
Neutralizer override switchWhen the switch is activated,the neutralizer override switch opens the neutralizer input line of the transmission electronic control module regardless of brake position. This switch is used to disable the neutralizer switch when neutralizing the transmission during braking is not desired.Ride Control Switch
Illustration 8 g00726666
Ride control switchThe ride control switch signals the mode that is selected by the operator to the ECM. The ride control switch has two input connections to the control: input 1 at connector contact 18 and input 3 at connector contact 19. When the operator selects AUTO mode, input 1 is open and input 3 is closed to +battery. When the ON mode is selected, input 1 is closed to +battery and input 3 is open. When OFF is selected, input 1 and input 3 are open.
Table 2
Status of the Ride Control Switch    
Mode     Switch Position     Input 1
Contact 18     Input 3
Contact 19    
ON