Dim Pot Input Short To Battery Or Open
Circuit Description
The dimmer output controls the intensity of the back-lighting of the cluster,
radio, I/P switch, HVAC control head, and the transmission range shifter assembly.
When the BCM receives the input voltage from the dimmer potentiometer over circuit
230 it converts it to a corresponding resistance value, and then to an output dimming
level on circuit 8.
The dim output pulse width modulated signal. Minimum dim pot input voltage corresponds
to maximum output duty cycle. Maximum dim pot voltage corresponds to minimum output
duty cycle.
The BCM also provides a Class II PWM dimming message which is used by the IP
cluster to provide dimming level control of the odometer backlight.
Conditions for Setting the DTC
| • | Unable to control dimming level |
| • | Dim pot voltage greater than 80% of battery voltage |
| • | Circuit 230 short to battery or open |
| • | Condition exists for 5 seconds |
Diagnostic Aids
| • | Check for poor connection at the BCM. |
| • | Inspect harness connectors for: |
| • | improper terminal mating |
| • | improperly formed or damaged terminals |
| • | poor terminal to wire connection (terminal crimped over wire insulation
and not conductors). |
| • | Inspect the wiring harness for damage. |
| • | If fault is suspected to be intermittent, wiggling harness wiring may
help in locating fault. |
