Solenoid Valve (Hydraulic Fan)
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| Illustration 1 | g00932126 |
Proportional Solenoid Valve | |
The solenoid valve is an output of the engine ECM. The solenoid valve meters out the pilot oil from the pressure and flow compensator valve on the hydraulic fan pump. The solenoid valve allows signal oil to flow to the hydraulic tank. The solenoid valve is used to control the speed of the hydraulic fan system. The solenoid valve is energized with a PWM signal that is sent by the ECM. The PWM signal acts as a source of variable current to activate the solenoid. As the current to the solenoid valve is increased, the flow of pilot oil to the hydraulic tank is increased.
The solenoid valve has a connector with two contacts. One contact receives power from the corresponding connector contact of the ECM (J1-43). The contacts for the solenoid valve return through contact J1-51 of the engine ECM.
Solenoid Valve (Ride Control)
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| Illustration 2 | g00932173 |
The on/off solenoid valves for the ride control system are outputs of the power train ECM. The on/off solenoid valve 1 will enable the flow of high pressure oil between the head end of the lift cylinders and the accumulator. The on/off solenoid valve 2 allows the oil in the rod end of the lift cylinders to flow to the hydraulic tank. When the on/off solenoid valve is energized by a constant voltage from the power train ECM, the oil will flow to the hydraulic tank. The on/off solenoid valve 1 has a connector with two contacts. One contact receives power from connector contact J1-18 of the ECM. The other contact joins together with the other solenoid valve and returns to connector contact J1-7 and J2-3 of the ECM. The on/off solenoid valve 2 has a connector with two contacts. One contact receives power from connector contact J1-12 of the ECM. The other contact joins together with the other solenoid valve and returns to connector contact J1-7 and J2-3 of the ECM.
Solenoid Valve (Fourth Function)
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| Illustration 3 | g00932216 |
The solenoid valve (fourth function) is a two-position valve. In the energized position, pilot oil is routed to the fourth function in the main control valve. When the solenoid valve is de-energized the pilot oil will flow to the tilt control valve. The solenoid valve allows the operator to change between the tilt function and the fourth function with a switch in the cab. The operator will use the tilt lever to operate the fourth function. The solenoid valves (fourth function) are equipped on the IT38G Series II Integrated Toolcarrier.
One contact receives current from the battery through wire 987-WH. The other contact goes to frame ground through wire 200-BK.
Solenoid Valve (Quick Coupler)
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| Illustration 4 | g00932303 |
The solenoid valve (quick coupler) is a three-position valve. The solenoid valve is used in order to lock the pins for the quick coupler. The solenoid valve is used in order to unlock the pins for the quick coupler. As the switch for the quick coupler in the cab is activated, current is sent to one coil of the solenoid valve. When the solenoid valve is energized, oil is diverted to the quick coupler cylinder. The coupler pins will lock. When the switch is deactivated, current is sent to the second coil in the solenoid valve. The oil is diverted to the rod end of the coupler cylinder. Then, the coupler pins are unlocked.
In the coil assembly for the solenoid valve (quick coupler), there are two coils. One coil controls the locking and the other coil controls the unlocking of the pins. The solenoid valve has a connector with four contacts. For coil 1, one contact receives power from the quick coupler switch through wire P976-BR. The other contact from the coil goes to ground through wire 200-BK. Solenoid valve 2 has two contacts. One contact receives power from the quick coupler switch through wire 779-WH. The other contact is common to wire 200-BK.
Detent Coils
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| Illustration 5 | g00935187 |
The detent coils are located within the pilot valve. The coils are used as an electromagnet, in order to hold the retainer in place when the control lever is moved to the end of travel. In the 938G Series II Wheel Loader, the detent coils for both the tilt function and the lift function will be energized when the key start switch is in the ON position. In the IT38G Series II Integrated Toolcarrier, the detent coils for both the tilt function and the lift function will be energized when the key start switch is in the ON position, and the kickout switch is activated. The detent coils for the float function and the detent coil for the auxiliary function are energized through the power train (ECM).
Reference: For additional information about the working of the detent coils in the pilot valve, refer to the Service Manual module Systems Operation and Testing and Adjusting, "Ride Control System".
The detent coil for the raise has a connector with two contacts. One contact is connected to the control group for the lift kickout. The contact is wire 761-GY. The other contact goes to cab ground. The contact is wire 200-BK.
The detent coil for the work tool positioner has a connector with two contacts. One contact is connected to the control group(s) for the tilt kickout. The contact is wire 961-BR. The other contact goes to cab ground. The contact is wire 200-BK .
The detent coil for the float function has a connector with two contacts. One contact is connected to contact 13 on the power train (ECM). The contact is wire G948-BR. The other contact goes to cab ground. The contact is wire 200-BK.
The detent coil for the auxiliary function (if equipped) has a connector with two contacts. One contact is connected to contact 13 on the power train (ECM). The contact is wire G948-BR. The other contact goes to cab ground. The contact is wire 200-BK.