GM Service Manual Online
For 1990-2009 cars only

Check Gauges Lamp

This indicator lamp is standard on all vehicles. This lamp comes on when the engine coolant temperature is too high or the engine oil pressure is too low. If this lamp comes on, check the gauges and refer to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls.

Low Coolant Lamp

This indicator lamp comes on when a low coolant condition exists. The low coolant module controls the warning lamp. For diagnostic information, refer to Instrument Cluster System Check in Engine Controls.

Charging System Warning System

The charging system warning system has an indicator lamp. One side of the bulb connects to the generator and the other side connects to the ignition. Refer to Starting System Check in Engine Electrical.

Malfunction Indicator Lamp (MIL)

The malfunction indicator lamp (MIL), or the SERVICE ENGINE SOON lamp, is part of the computerized engine control system. Refer to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls.

Brake Warning System

The brake warning system has a differential switch mounted on the brake combination valve. The indicator lamp is mounted in the instrument cluster.

Electronic PRNDL

Vehicles with automatic transmissions have an electronic PRNDL. This system uses signals from the neutral safety back up switch on the side of the transmission. Signals from this switch determine which light emitting diodes (LED) in the electronic PRNDL will illuminate.

Because the system is entirely electronic, no adjustment is necessary. For diagnostic information, refer to Instrument Cluster System Check in Engine Controls.