Pinpoint Test F: One or More Illumination Source(S) Is Inoperative

Instrument Cluster and Panel Illumination


Pinpoint TestsPinpoint Test F: One Or More Illumination Source(s) Is Inoperative

Refer to wiring Diagram Set 71, Cluster and Panel Illumination for schematic and connector information. Diagrams By Number

Normal Operation

The instrument panel dimmer switch provides variable voltage to individual illumination sources through circuit VLN18 (BU/WH). The headlamp and Four-Wheel Drive (4WD) mode switches are grounded through circuit GD161 (BK/YE).

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors
- Headlamp switch
- 4WD mode switch



PINPOINT TEST F: ONE OR MORE ILLUMINATION SOURCE(S) IS INOPERATIVE

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery.

-------------------------------------------------
F1 CHECK THE INOPERATIVE ILLUMINATION SOURCE


- Place the headlamp switch in the PARKING LAMPS ON position.
- Rotate the instrument panel dimmer switch to the full illumination position.
- Observe the illumination.
- Are all of the illumination sources inoperative?

Yes
Go To Pinpoint Test A. Pinpoint Test A: The Control Illumination Is Inoperative

No
If the headlamp switch illumination is inoperative, GO to F2.

If the 4WD mode switch illumination is inoperative, GO to F4.

-------------------------------------------------
F2 CHECK CIRCUIT VLN18 (BU/WH) FOR AN OPEN AT THE HEADLAMP SWITCH


- Disconnect: Headlamp Switch C205.
- Connect a fused jumper wire between the headlamp switch C205-5, circuit CLS30 (VT/WH), harness side and the headlamp switch C205-10, circuit CBP23 (WH/RD), harness side.




- Measure the voltage between the headlamp switch C205-8, circuit VLN18 (BU/WH), harness side and ground.




- Is the voltage greater than 10 volts?

Yes
REMOVE the fused jumper wire. GO to F3.

No
REPAIR the circuit. TEST the system for normal operation.

-------------------------------------------------
F3 CHECK CIRCUIT GD161 (BK/YE) FOR AN OPEN AT THE HEADLAMP SWITCH


- Disconnect: Negative Battery Cable.
- Measure the resistance between the headlamp switch C205-3, circuit GD161 (BK/YE), harness side and ground.




- Is the resistance less than 5 ohms?

Yes
INSTALL a new headlamp switch. TEST the system for normal operation.

No
REPAIR the circuit. TEST the system for normal operation.

-------------------------------------------------
F4 CHECK CIRCUIT VLN18 (BU/WH) FOR AN OPEN AT THE 4WD MODE SWITCH


- Disconnect: 4WD Mode Switch C284.
- Place the headlamp switch in the PARKING LAMPS ON position.
- Rotate the instrument panel dimmer switch to the full illumination position.
- Measure the voltage between the 4WD mode switch C284-1, circuit VLN18 (BU/WH), harness side and ground.




- Is the voltage greater than 10 volts?

Yes
GO to F5.

No
REPAIR the circuit. TEST the system for normal operation.

-------------------------------------------------
F5 CHECK CIRCUIT GD161 (BK/YE) FOR AN OPEN AT THE 4WD MODE SWITCH


- Place the headlamp switch in the OFF position.
- Disconnect: Negative Battery Cable.
- Measure the resistance between the 4WD mode switch C284-4, circuit GD161 (BK/YE), harness side and ground.




- Is the resistance less than 5 ohms?

Yes
INSTALL a new 4WD mode select switch. TEST the system for normal operation.

No
REPAIR the circuit. TEST the system for normal operation.

-------------------------------------------------