Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSGMC1999FORWARD CONTROL 5.7 R, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 527 (CELLULAR COMMUNICATION SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESONSTAR ONE OR MORE BUTTONS INOPERATIVE
1999 GMC Forward Control 5.7 R, Automatic
OnStar One or More Buttons Inoperative
1999 GMC Forward Control 5.7 R, AutomaticSECTION OnStar One or More Buttons Inoperative
WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.
OnStar One or More Buttons Inoperative
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| Schematic Reference: OnStar Schematics Connector End View Reference: Cellular Communication Connector End Views |
||||
| 1 | Did you perform the Cellular Communication Diagnostic System Check? | - | Go to Step 2 | Go to Diagnostic System Check - Cellular Communication |
| 2 |
IMPORTANT:
Contact the OnStar® Call Center first before pressing the emergency button in order to notify them of the test.
|
- | Go to Step 4 | Go to Step 3 |
| 3 | Are any buttons intermittent or inoperative? | - | Go to Step 7 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems |
| 4 |
|
9 V | Go to Step 6 | Go to Step 5 |
| 5 | Test the Keypad Supply Voltage circuit for an open or short. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 11 | Go to Step 8 |
| 6 | Test the Keypad Signal circuit for an open or short. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 11 | Go to Step 9 |
| 7 | Inspect for poor connections at the harness connector of the OnStar® button assembly. 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 11 | Go to Step 9 |
| 8 | Inspect for poor connections at the harness connector of the VCIM. 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 11 | Go to Step 10 |
| 9 | Replace the OnStar® button assembly. Refer to OnStar Button Assembly Replacement in Stationary Windows. Did you complete the replacement? |
- | Go to Step 11 | - |
| 10 |
IMPORTANT:
Perform the OnStar® setup procedure. Replace the Communication Interface Module. Refer to Communication Interface Module Replacement .Did you complete the replacement? |
- | Go to Step 11 | - |
| 11 | Operate the system in order to verify the repair. Did you correct the condition? |
- | System OK | Go to Step 2 |
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.