Model 8210/8250 Maintenance Manual Section 7. Component Procedures
Electrical Components Switches (General)
Publication: 1146945/001, Revised: 25 Sep 2018 7-79
Switches (General)
NOTE: For replacement parts information refer
to the Parts Manual.
Refer to the Electrical Schematics to identify the
electrical circuit location of the switch.
Testing/Inspecting Switches
Examine the switch for signs of arcing,
overheating, discoloration, cracking, or other
physical damage. Replace the switch if you see
such damage.
1. To test a switch, isolate it from the
electrical circuit. Do this by removing all
the connections from the switch, making
sure all wires are labeled and identified for
later reconnection.
2. Use an ohmmeter set to a low resistance
scale to measure the resistance across the
switch. In the closed position, the switch
must have a resistance of less than 1 ohm.
In an open position, the switch must show
a resistance greater than 10 megohms.
Main ON/OFF Switch
A 2-position keyless (rocker) Main ON/OFF
switch (SW1) is standard equipment. When in
the OFF ( O ) position, battery power to all
control functions is interrupted. When in the
ON ( | ) position, battery potential is provided to
all control functions via the traction amplifier.
See Figure 7-93.
Figure 7-93. Main ON/OFF Switch (SW1) - Standard
6349_023.jpg
Main ON/OFF Switch Inspection
1. With the battery plugged in and the Main
ON/OFF switch in the ON position, battery
voltage B+ must be present on the two
terminals of the switch.
2. Test the Main ON/OFF switch with an
ohmmeter after disconnecting the battery
and removing the wires from the switch
terminals.
In the OFF position, the ohmmeter must read
greater than 1 megohm, and in the ON position,
the ohmmeter must read less than 1 ohm. If
not, replace the switch.
Main ON/OFF Switch Removal
1. If equipped with the optional keypad,
press the red OFF ( O ) key. Place the Main
ON/OFF Switch in the OFF position.
Disconnect the battery connector from the
truck.
2. Remove the tractor covers.
3. Disconnect the wires from the switch.
4. Remove the Main ON/OFF switch.
Main ON/OFF Switch Installation
1. Install the new Main ON/OFF switch.
2. Connect the wires to the new Main
ON/OFF switch terminals.
3. Reconnect the battery connector and verify
operation.
4. Install the tractor covers.
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