Schematic Reference: OnStar Schematics

DEFINITION: The OnStar® Call Center cannot control the Horns, Door unlock or the Exterior lamps.

Did you perform the Cellular Communication Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Cellular Communication

1. Turn ON the ignition, with the engine OFF.
2. Press the OnStar® call center button.
3. Ask the OnStar® operator to command on the system with the concern (Horns, Door Unlock or Exterior Lamps).

Does system operate properly?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

Manually test the system with the concern.

Does the system with the concern operate properly?

Go to Step 4

Go to Diagnostic Starting Point - Horns in Horns, Diagnostic Starting Point - Lighting Systems in Lighting Systems, Diagnostic Starting Point - Doors in Doors

Test the appropriate circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 6

Go to Step 5

Inspect for poor connections at the harness connector of the vehicle interface unit (VIU). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 6

Use the scan tool to access the STID, ESN and Transceiver I.D. and contact the General Motors Technical Assistance Center

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2