"Volts" Telltale

TEST CONDITION(S)
None

FAILURE CONDITION(S)
1)Generator charge input (terminal L) low.
OR
1)Code B410 set.

ACTION TAKEN
1) Light "Volts" telltale on Instrument Panel Cluster (IPC).

DESCRIPTION
The BCM monitors the generator L-terminal input on pin 3C13. This input indicates whether the generator is charging or not. If the generator is not charging. it grounds the L-terminal. If the generator is charging. it
leaves the L-terminal ungrounded. The BCM uses this input to determine whether the "Volts" telltale should be illuminated. Whenever the L-terminal input is low or BCM code B410 is set, the BCM will command the IPC to turn on the "Volts" telltale via the UART dataline.


NOTE When the engine is not running, the generator will not be charging. Therefore, it is normal for the "Volts" telltale to illuminate with the ignition on, the engine not running. This is a bulb test mode that allows the driver to verify that the "Volts" telltale is operational.

DIAGNOSIS
Condition Possible Causes
Erroneous Telltale short to ground on circuit 225, or a failed generator
No Telltale open in circuit 225, open in circuit 250, or open in generator circuitry