Diagnostic Instructions
Circuit/System Description
The vehicle communication interface module (VCIM) commands on the red or green LED by supplying ground to either the keypad red signal circuit or keypad green signal circuit.
Reference Information
Schematic Reference
OnStar Schematics
Connector End View Reference
Entertainment/Communication Connector End Views
Description and Operation
OnStar Description and Operation
Electrical Information Reference
Circuit/System Verification
Ignition ON, With the scan tool command the VCIM to turn on the red and green LED.
| ⇒ | If the red or green LED indicators do not illuminate, go to Circuit/System Testing. |
Circuit/System Testing
- Ignition OFF, disconnect the inside rearview mirror harness connector .
- Ignition ON,test for less than 1 ohm between the inside rearview mirror harness connector terminal E and ground.
| ⇒ | If greater than specified value repair open or high resistance. or replace the VCIM. |
- With a scan tool command the green LED ON. Test for 9.2 to 10.2 volts at the inside rearview mirror harness connector terminal F and ground.
| ⇒ | If 9.2 to 10.2 volts is not present with the green LED is commanded ON, repair open or high resistance. or replace the VCIM |
- With a scan tool command the red LED ON. Test for 9.2 to 10.2 volts the inside rearview mirror harness connector terminal G and ground.
| ⇒ | If 9.2 to 10.2 volts is present with the red LED is commanded ON, repair open or high resistance. or replace the VCIM |
- If all circuits test normal, test or replace the Rear View Mirror.
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
