Test E

PINPOINT TEST E: THE INSTRUMENT PANEL ILLUMINATION DOES NOT DIM

Test E1-E2:

Test E2-E4:

Test E5-E7:

Test E8:

Normal Operation
The headlamp switch supplies the instrument cluster with the headlamp switch position status. The dimmer switch provides the instrument cluster with the dimmer control status through signal circuit 8-LE10 (WH/BK) and return circuit 9-LE10 (BN/YE). The instrument cluster sends the illumination message to the front electronic module (FEM) over the standard corporate protocol (SCP) communication network, circuits 4-EG8 (GY/VT) and 5-EG8 (BU/WH), based upon the dimmer switch position. The FEM is supplied with illumination power through circuit 29S-DK22 whenever the switched system power (SSP) is energized. When the headlamp switch is in the PARK, HEADLAMP, or AUTOLAMP ON position, the instrument cluster sends the FEM an illumination message and the FEM, in turn, provides pulse width modulation (PWM) power to the interior auxiliary junction box through circuit 64S-LH5 (BU/YE). The interior auxiliary junction box separates the PWM power and supplies it to sub-illumination sources through circuits 64S-LH4 (BU/BK), 64S-LH1 (BU), 64S-LK9 (BU/WH), 64S-LH16 (BU/WH), 64S-LH1 (BU), and the central junction box (CJB) through circuit 64S-AD2 (BU/RD). The CJB separates the PWM power and also supplies it to sub-illumination sources through circuits 64S-LH2 (BU/RD) and 64S-LH33 (BU/BK). The sub-illumination sources then provide the PWM power to the individual illuminating sources.

Possible Causes
- circuit 8-LE10 (WH/BK) open, short to power or ground
- circuit 9-LE10 (BN/YE) open, short to power or ground
- instrument panel dimmer switch
- dimmer module