Pinpoint Test C: All Dimmable Switch Illumination Is Always On

Instrument Cluster and Panel Illumination

Pinpoint Test C: All Dimmable Switch Illumination Is Always On

Normal Operation

Based on input received from the instrument panel dimmer switch, the Smart Junction Box (SJB) sends a Pulse Width Modulated (PWM) voltage to the hardwired dimmable switches.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- SJB (Smart Junction Box)

PINPOINT TEST C : ALL DIMMABLE SWITCH ILLUMINATION IS ALWAYS ON

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

C1 CHECK THE EXTERIOR LIGHTING

- Place the headlamp switch in the OFF position.

- Observe the exterior lighting components.

Are any exterior lighting components illuminated?

Yes
REFER to Lighting and Horns.

No
GO to C2.

C2 CHECK THE SJB (Smart Junction Box) BACKLIGHTING OUTPUT CIRCUIT FOR A SHORT TO VOLTAGE

- Disconnect: SJB (Smart Junction Box) C2280B.

- Ignition ON.

Do the dimmable backlighted components continue to illuminate?

Yes
REPAIR the short to voltage. CLEAR the DTCs. REPEAT the self-test.

No
GO to C3.

C3 CHECK FOR CORRECT SJB (Smart Junction Box) OPERATION

- Disconnect all the SJB (Smart Junction Box) connectors.

- Check for:
- corrosion

- damaged pins

- pushed-out pins


- Connect all the SJB (Smart Junction Box) connectors and make sure they seat correctly.

- Operate the system and verify the concern is still present.

Is the concern still present?

Yes
INSTALL a new SJB (Smart Junction Box). TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.