Checking Aftermarket Accessories

CHECKING AFTERMARKET ACCESSORIES

Do not connect aftermarket accessories into the following circuits:
- SIR circuits, all such circuits are indicated on circuit diagrams with the SIR symbol.

CAUTION: Refer to SIR Caution in Service Precautions.

OBD II circuits, all such circuits are indicated on circuit diagrams with the OBD II symbol.

NOTE: Refer to OBD II Symbol Description Notice in Service Precautions.

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.