ENGINE HIGH IDLE DOES NOT OPERATE (M977, M985)

TM 9-2320-279-20-1

Troubleshooting Malfunctions (Cont)

Tab/e 2-9. Troubleshooting (Cont)

Malfunction

Test or Inspection

Corrective Action

Step 1.

Check for defective engine speed control wiring. Disconnect plug from engine high idle as-

sembly. Set multimeter to test for 24 Set Set ENGINE and PTO ENGAGE switches to ON

and crane POWER switch to OFF. Place negative (-) probe in socket No. 4 and touch posi-

tive (+) probe to PIN No. 1. Meter should show 24 vdc.

If meter does not show 24 vdc, trace wiring and find problem. Refer to FO-1, Electric

Diagram.

Check for defective crane power wiring. Disconnect plug from engine high idle assembly,

Step 2.

Set multimeter to test for 24 vdc. Set crane POWER switch to ON. Place negative (-)

probe in socket No. 4 and positive (+) probe to PIN No. 2. Meter should show 24 vdc.

If meter does not show 24 vdc, repair No. 310 wire to crane junction box. If problem

is not solved, report problem to the supervisor.

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