2001-2004 Saab 9-5 & 9-3 OnStar GPS Module: Why a Dead Part Still Causes Problems

The Obsolete OnStar Service: A Critical Starting Point

Before diagnosing any issues, it's essential to understand that the core services this module was built for are no longer active. The analog cellular network it relied on was shut down by the FCC in 2008, and the later 2G networks have also been decommissioned. This means that even with a perfectly functioning module, you cannot make OnStar emergency calls, use remote services, or subscribe to the service. Replacing a faulty module will not bring these features back. The reasons to replace this module today are solely to fix collateral issues caused by its failure.

Symptoms of a Failing OnStar Module

When this module fails, it doesn't just die quietly. Its failure can create frustrating electrical problems in your Saab 9-5 or 9-3. Here are the most common symptoms:

• Parasitic Battery Drain: This is the most frequent complaint. A faulty OnStar module can fail to enter its low-power "sleep" mode when the car is off. It remains active, continuously drawing power and draining the battery, often over a period of two to four days. This issue can occur even if you've never had an OnStar subscription.
• Factory Navigation Malfunctions: If your Saab is equipped with the factory navigation system, a failed OnStar module can cause the map to show an incorrect vehicle position or no position at all. This happens because the GPS antenna signal is routed through the OnStar module before it reaches the navigation head unit. You may also experience the clock displaying the wrong time, as it relies on the GPS signal for synchronization.
• "OnStar Malfunction" Message: A persistent error message may appear on the Saab Information Display (SID), which can be an annoyance during every drive.
• Loss of Audio or Infotainment Functions (2003 9-3): On the 2003 Saab 9-3 Convertible and Hatchback, the audio and infotainment components are connected in a fiber-optic loop. If the OnStar module fails, it can break this communication "ring," causing other components like the amplifier or CD changer to stop working.

Diagnosing the Module

If you suspect a parasitic battery drain, you can perform a draw test. This involves disconnecting the negative battery terminal and connecting a multimeter in series to measure the amperage draw after the vehicle has been off for at least 30 minutes, allowing all modules to go to sleep. A normal draw should be very low (typically under 50 milliamps). If the draw is high, you can start pulling fuses one by one. The OnStar module fuse is a common culprit. If pulling its fuse causes the draw to drop significantly, you've likely found the problem. For definitive diagnosis of communication or GPS signal issues, a Saab-specific Tech 2 diagnostic scanner is required to communicate with the module and read any specific trouble codes.

Buying a Used GPS Navigation Control Module

Since new OEM parts are no longer available, a quality used module is the only option. Here’s what to look for:

• Match the Part Number: This is the most critical step. There are several compatible part numbers, but you must match one from your original module to the replacement. Check the label on your existing unit and compare it to the seller's listing.
• Inspect the Connectors: Ask the seller for clear photos of the connector pins. Look for any signs of corrosion (green or white crust), which can indicate water damage and lead to a short lifespan.
• Vehicle Fitment: Double-check that the module is from a compatible vehicle: a 2001-2004 Saab 9-5 or a 2001-2003 Saab 9-3 (Convertible/Hatchback only).
• Why Used OEM is Best: There are no new aftermarket versions of this specific, complex module. A recycled OEM part is the only reliable and available solution. It was designed by Saab to integrate perfectly with the vehicle's systems, provided it is programmed correctly.

Replacement, Programming, and Alternatives

Module Location

• 2001-2004 Saab 9-5: The module is typically located under the luggage compartment floor in wagon (5-door) models or behind the glove box in sedan models.
• 2001-2003 Saab 9-3: The module is located in the trunk, often mounted on a bracket behind the side trim panel.

Programming is Required

The DIY Alternative: Bypassing the Module

If you do not use the factory navigation and simply want to eliminate the error messages or battery drain, you can bypass the module entirely. For the 2003 9-3 models that use a fiber optic loop, you can purchase a simple fiber optic bypass adapter. This adapter connects the incoming and outgoing fiber optic cables together, completing the circuit and allowing the rest of your audio system to function. For other models, simply unplugging the module may solve a battery drain, but it will set permanent trouble codes. The correct way to remove it from the system is to have a technician with a Tech 2 reprogram the vehicle to know the module is no longer present.

Cost of Replacing the OnStar Module

Frequently Asked Questions