BUCKET AS-ROCK 3639843 - Caterpillar

Illustration 1 g01276592Specification
This test measures the voltage drop across two of the poles for the key start switch. The voltage drop between test point (5) and test point (6) represents the "STAR" pole. The voltage drop between test point (5) and test point (8) represents the "RELAY" pole.A voltage drop will cause the indicator lamp for the key start switch to turn ON. The voltage drop can be across one or both of the poles. The voltage drop must be larger than 2.50 0.15 volts. The lamp turned ON in order to indicate a defect. A defect can be indicated during any Test Step.The possible causes of this condition are listed:
Open pole on the switch
Closed switches with excessive voltage drops
Poles on the switch with welded contactsNote: The keyswitch START position is open for three of the tests. The three tests are "Test Setup A, Hookup", "Test Step C, Start Aid", and "Test Step D, High Idle". The indicator for the keyswitch is turned ON during the steps. This is correct.Information for Other Circuits
An inhibitor for the key start switch instead of the key start switch can cause a failure during the "Test Step B, Crank". Direct drive machines use a neutral start switch to inhibit the starting of the engine.Switches that inhibit the starting of the engine (N) are always installed between test point 5 and test point 6.The wiring harness and the connections for the wiring harness are also checked in this test. Refer to the wiring schematic for the machine that is being serviced for the location of the components. An open in the harness will indicate a defect.