Checking Aftermarket Accessories

Do not connect aftermarket accessories into the following circuits:

CAUTION: Refer to SIR Service Precautions Caution in Cautions and Notices.

^ SIR circuits, all such circuits are indicated on circuit diagrams with the SIR symbol.

NOTE: Refer to OBD II Symbol Description Notice in Cautions and Notices.

^ OBDII circuits, all such circuits are indicated on circuit diagrams with the OBDII 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.

Check the thoroughness of the repair by performing a final system check on the headlamp circuit. This of course means making sure that both high beams, both low beams, and the high beam indicator are working.

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.