Toro Groundmaster 31900, Service Manual

Page: 216 / 355

Lift/Lower Switch
POSITION CLOSED
CIRCUITS
INCREASE
SPEED
2 + 3, 5 + 6
NEUTRAL NONE
DECREASE
SPEED
2 + 1, 5 + 4
The lift/lower switch is located on the operator’s console. When the front of
the switch is depressed, the lift arms will lower. When the rear of the switch
is depressed, the lift arms will lift. When raising the lift arms, the lift arms will
remain in position if the switch is released. The engine must be running to allow
the lift arms to be raised.
The TDM display/controller monitors signals from the lift/lower switch. When the
front of the switch is depressed, the TDM display/controller energizes solenoid
valve coil SV1 causing the valve to shift and the lift cylinder to extend to raise the
lift arms. When the rear of the switch is depressed, the TDM display/controller
energizes solenoid valve coil SV2 causing the valve to shift allowing the hydraulic
fluid in the lift cylinder to escape. The weight of the cutting unit (or attachment)
retracts the lift cylinder to lower the lift arms.
Testing the Lift/Lower Switch
The lift/lower switch and its circuit wiring can be tested using the TDM
display/controller; refer to
Using the TDM Display/Controller Screens for
Troubleshooting (page 3–12) . If testing determines that the switch and circuit
wiring are not functioning correctly, proceed with the following test procedure:
1. Park the machine on a level surface, lower the cutting unit (or attachment),
engage the parking brake, set the key switch to the O
FF
position and remove
the key from the key switch.
2. Disconnect the battery negative (-) cable at the battery; refer to Removing
and Installing the Battery (page 6–64) .
3. Remove the operator’s console covers; refer to Removing and Installing the
Operator’s Console Covers (page 7–23) .
4. Disconnect the wire harness connector from the switch and remove the
switch from the console if necessary. Check the switch and the harness
connector for damage or corrosion and clean or repair if necessary.
5. Use a multimeter (ohms setting) and the preceding table to determine
whether continuity exists between the various terminals for each switch
position.
6. Replace the switch if necessary.
7. If the switch tests correctly and a circuit problem still exists, check the wire
harnesses; refer to Appendix A (page A–1) .
8. Install the switch and connect the wire harness after testing.
9. Install the console covers.
10. Connect the battery negative (-) cable at the battery.
Electrical System: Testing the Electrical Components Page 6–24 Groundsmaster ® 3200, 3300 and 3310
19240SL Rev A