Checking Aftermarket Accessories

IMPORTANT: Do not connect aftermarket accessories into the following circuits:
^ SIR circuits, all such circuits are indicated on circuit diagrams with the SIR symbol. Refer to SIR Service Precautions Caution in Cautions and Notices.
^ OBDII circuits, all such circuits are indicated on circuit diagrams with the OBDII symbol. Refer to OBDII Symbol Description Notice in Cautions and Notices.

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.