1. Make these input tests at the connector.
   - If any test indicates a problem, find and correct the cause, then recheck the system.
   - If all input tests prove OK, the control unit must be faulty; replace it.

   Cavity | Wire | Test condition | Test: Desired result | Possible cause if result is not obtained
   --- | --- | --- | --- | ---
   7 | YEL | Ignition switch ON (II) or START (III) | Check for voltage to ground: There should be battery voltage. |
   - Blown No. 21 (10 A) fuse in the driver's under-dash fuse/relay box
   - An open in the wire
   1 | WHT | Ignition switch ON (II) |
   - Blown No. 7 (7.5 A) fuse in the driver's under-dash fuse/relay box
   - An open in the wire
   4 | LT GRN | Combination switch in the OFF, PARK, and AUTO positions | Check for voltage to ground: There should be battery voltage. |
   - Faulty headlight relay 1 or 2
   - An open in the wire
   8 | BLK | Under all conditions | Check for continuity to ground: There should be continuity. |
   - Poor ground (G506)
   - An open in the wire
   9
   11 | BLU | Driver's door open * | Check for voltage to ground: There should be 1 V or less. |
   - Faulty driver's door switch
   - An open in the wire
   2 | WHT | Combination light switch ON (Except ‘‘AUTO'') | Check for continuity to ground: There should be continuity. |
   - Faulty combination light switch
   - Poor ground (G501, G601)
   - An open in the wire

   *: | Reconnect the 14P connector to the control unit

   NOTE: Before testing, connect a voltmeter and jumper wires as shown:

Cavity | Wire | Test condition | Test: Desired result | Possible cause if result is not obtained
--- | --- | --- | --- | ---
6 | RED | Cover the automatic lighting sensor * | Check for voltage between the No. 6 terminal and body ground: There should be 1 V or less. |

- Faulty automatic lighting sensor
- An open in the wire

Shine light on the automatic lighting sensor | Check for voltage between the No. 6 terminal and body ground: There should be 5 V or more. |

- Faulty automatic lighting sensor
- An open in the wire

*: | The automatic lighting sensor is located in the middle of dashboard. Cut the light off completely with a dark cloth.