Malfunction of the Ignition Switch Power Supply System

Malfunction of the ignition switch power supply system










TECHNICAL DESCRIPTION (COMMENT)

When the power supply system of ignition switch has a problem, none of the equipment and system connected to the ignition switch works even if the ignition switch is operated.

TROUBLESHOOTING HINTS

- Malfunction of the ignition switch
- Damaged harness wires and connectors

DIAGNOSIS

Required Special Tools:

- MB992006: Extra fine probe
- MB991223: Harness set

STEP 1. Check ignition switch connector C-308 for loose, corroded or damaged terminals, or terminals pushed back in the connector.





Q. Is ignition switch connector C-308 in good condition?

YES Go to Step 2.

NO Repair the defective connector.

STEP 2. Check the battery power supply circuit to the ignition switch. Measure the voltage at ignition switch connector C-308.

(1)Disconnect the connector, and measure at the wiring harness side.









(2)Measure the voltage between terminal 1 and ground.

- The voltage should measure approximately 12 volts (battery positive voltage).

Q. Is the measured voltage approximately 12 volts (battery positive voltage)?

YES Go to Step 4.

NO Go to Step 3.

STEP 3. Check the Wiring harness between ignition switch connector C-308 (terminal No.1) and fusible link (4).





NOTE:
Prior to the wiring harness inspection, check intermediate connector C-24, and repair if necessary.

- Check the battery power supply line for open circuit.

Q. Is the check result normal?

YES Go to Step 5.

NO Repair the wiring harness.

STEP 4. Check the ignition switch.

Remove the ignition switch. Then check continuity between the switch terminal.





Q. Is the ignition switch in good condition?

YES Go to Step 5.
NO Replace the ignition switch.
STEP 5. Retest the system.

Q. When the ignition switch is operated, do the equipment and system work normally?

YES The trouble can be an intermittent malfunction How to Cope With Intermittent Malfunctions).
NO Return to Step 1.