Diesel Data: Automotive Repair

Pinpoint Test D: No Power in START




Steering Column Switches

Pinpoint Tests

Pinpoint Test D: No Power in START

Normal Operation

When the ignition switch is placed in the START position, fused ignition voltage is sent to the Battery Junction Box (BJB) along circuit CDC35 (BU/WH).

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Ignition switch


PINPOINT TEST D: NO POWER IN START

NOTICE: Use the Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multi-meter probes.

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D1 CHECK THE IGNITION SWITCH


- Ignition OFF.
- Disconnect: Ignition Switch C250.
- Carry out the Ignition Switch - Electrical Component Test.
- Is the ignition switch OK?

Yes
GO to D2.

No
INSTALL a new ignition switch. REFER to Ignition Switch Ignition Switch. TEST the system for normal operation.

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D2 CHECK THE IGNITION START CIRCUIT FOR AN OPEN


- Disconnect: Start Diode.
- Measure the resistance between ignition switch C250-7, circuit CDC35 (BU/WH), harness side and the start diode input socket.




- Is the resistance less than 5 ohms?

Yes
GO to D3.

No
REPAIR circuit CDC35 (BU/WH). TEST the system for normal operation.

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D3 CHECK THE IGNITION START CIRCUIT FOR A SHORT TO GROUND


- Measure the resistance between ignition switch C250-7, circuit CDC35 (BU/WH), harness side and ground.




- Is the resistance greater than 10,000 ohms?

Yes
REFER to Starting System Testing and Inspection to diagnose the starting system.

No
REPAIR circuit CDC35 (BU/WH). TEST the system for normal operation.

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