FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
Courtesy of Operation CHARM: Car repair manuals for everyone.

Test C: One or More Smart Junction Box (SJB) Controlled Illumination Source(s) Is Inoperative

PINPOINT TEST C: ONE OR MORE SMART JUNCTION BOX (SJB) CONTROLLED ILLUMINATION SOURCE(S) IS INOPERATIVE


C1-C4:






C4-C5:






C6-C8:






C8-C9:






C9-C11:






C11-C12:






Normal Operation - Dimmable Backlighting
With the parking lamps ON, a voltage signal is supplied to the instrument panel dimmer switch through circuit 1036 (BN/WH) from the smart junction box (SJB). The dimmer switch passes this voltage through a variable resistor and then returns the signal to the SJB on circuit 1035 (OG/RD). The SJB uses the return signal to determine the backlighting intensity desired by the operator. A pulse-width modulated (PWM) signal is sent from the SJB to each of the dimmable backlights maintaining the operator's desired level of lighting intensity.

Normal Operation - Non-Dimmable Backlighting
When the ignition switch is placed in the ACCY or the ON position, a voltage signal is supplied to the SJB. The SJB activates the accessory delay relay, supplying voltage to the non-dimmable backlights.

Possible Causes
- fuse
- circuit 19 (LB/RD) open or short to ground
- circuit 203 (OG/LB) open or short to ground
- circuit 293 (OG/RD) open or short to ground
- circuit 333 (YE/RD) open or short to ground
- circuit 984 (YE/LB) open or short to ground
- circuit 985 (RD/LB) open or short to ground
- circuit 1205 (BK) open
- circuit 1403 (BK/WH) open or short to ground
- circuit 1405 (LB/BK) open
- circuit 1425 (GY/WH) open or short to ground
- circuit 2023 (YE/LB) open or short to ground
- circuit 2029 (LB/WH) open or short to ground
- circuit 2030 (YE/WH) open or short to ground
- illuminated component
- clockspring
- accessory delay relay
- SJB