Checking Aftermarket Accessories
WARNING: This page does not describe the selected car, but rather 12 other vehicles, including the 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, and 2003 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.
WARNING:
When you are performing service on or near the SIR components or the SIR wiring, you must disable the SIR system. See DISABLING & ACTIVATING AIR BAG SYSTEM in appropriate AIR BAG RESTRAINT SYSTEMS article in RESTRAINTS. Failure to follow the correct procedure could cause air bag deployment, personal injury, or unnecessary SIR system repairs.
NOTE:
The OBD II symbol is used on the circuit diagrams in order to alert the technician that the circuit is essential for proper OBD II emission control circuit operation. Any circuit which fails and causes the Malfunction Indicator Lamp (MIL) to turn ON, or causes emissions-related component damage, is identified as an OBD II circuit.
Do not connect aftermarket accessories into the SIR circuits (all such circuits are indicated on circuit diagrams with the SIR symbol) and the OBD II circuits (all such circuits are indicated on circuit diagrams with the OBD II symbol).
Always check for aftermarket accessories (non-OEM) as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems.
Possible causes of vehicle problems related to aftermarket accessories include:
- Power feeds connected to points other than the battery
- Antenna location.
- Transceiver wiring located too close to vehicle electronic modules or wiring.
- Poor shielding or poor connectors on antenna feed line.
- Check for recent service bulletins detailing installation guidelines for aftermarket accessories.