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For 1990-2009 cars only

Exterior Lights Circuit Description Pont, Chevy Domestic, Gulf States

Daytime Running Lamps (Chevrolet Domestic, Gulf States, Pontiac Canada)

The daytime running lamps (DRL) module is designed to automatically operate the front park/turn lamps through the park lamp feed circuit and the low beam headlamps through the headlamp switch output circuit, depending on the outside light conditions. The DRL control module operates in 2 modes:

    • The day mode allows the two front turn signal lamps to be on and non-flashing.
    • The night mode allows the following components to be on:
       - Low beam headlamps
       - Front side marker lamps
       - Park/turn lamps
       - Tail lamps
       - License lamps
       - Tail/stop/turn lamps
       - Tail/stop lamps (Chevrolet)

The DRL module operates in the night mode when the DRL ambient light sensor senses darkness. When this happens, the night mode contacts close, and voltage is applied to the headlamps and the exterior lights through the same circuit path as when the headlamp switch is in the HEAD position.

The DRL module turns off the headlamps when the engine stalls with the DRL in the night mode. The side marker lamps, the park/turn lamps and the tail lamps are on while the engine is cranking. The headlamp switch operates as usual.

Daytime Running Lamps (DRL) Ambient Light Sensor Input

The DRL ambient light sensor is a light sensitive variable resistor. The DRL ambient light sensor decreases in resistance as outside light intensity increases. The DRL module measures the voltage drop across the DRL ambient light sensor. The DRL module then determines whether the day mode or the night mode should be in operation.

Daytime Running Lamps (Pontiac Domestic)

The daytime running lamps (DRL) module is designed to automatically turn on the low beam headlamps through the headlamp switch output circuit and the front park/turn lamps through the park lamp feed circuit when the following is true:

    • The ignition switch is in the RUN position.
    • The headlamps are off.
    • The park brake is off.

The ambient light sensor is replaced by a jumper.

Park Brake Input

The DRL module will not operate any headlamps or exterior lamps if the park brake is applied before the ignition switch is turned to the RUN position. This allows the driver to start the vehicle and keep the headlamps off as long as the park brake is applied. The DRL module activates the headlamps when the park brake is released with the ignition switch in the RUN position. The headlamps will not turn off if the park brake is applied after the ignition switch is turned to the RUN position.

Front Park/Turn and Front Side Marker

Whenever the park lamps or the headlamps are on, voltage is applied from the TAIL LPS fuse 5 through the headlamp switch and the park lamp feed circuit to both the front side marker lamps and the front park/turn lamps.

Tail/Stop (Chevrolet), Tail/Stop/Turn (Pontiac), Rear Side Marker, Tail and License Plate Lamps

Voltage is applied at all times from the TAIL LPS fuse 5 to the headlamp switch and the daytime running lamps (DRL) module through circuit 240. Voltage is applied to the park lamp feed circuit when the headlamp switch is in the PARK or the HEAD position. Voltage then flows to all tail/stop lamps (Chevrolet), the tail/stop/turn (Pontiac) lamps, the rear side marker lamps, the tail lamps, and the license plate lamps, turning them on.

Turn Signal Lamps

Voltage is applied from the TURN B/U fuse 2 to the normally closed pole of the turn/hazard switch assembly (turn signal switch) when the ignition is in the RUN position. The voltage then flows through circuit 141 to the turn signal lamp flasher. Current flow heats the timing element in the turn signal lamp flasher causing the timing element to continuously open and close.

With the turn signal switch in the left turn position, voltage is applied through two circuits. Voltage flows through the left turn signal switch output circuit at terminal H of harness connector C216 and the left rear stop/turn lamp feed circuit at terminal M of C216. Voltage also flows through the left rear stop/turn lamp feed circuit to the left rear turn signal lamp. Voltage flows through the left turn signal switch output circuit to the instrument cluster for the left turn indicator and to the daytime running lamps module. Voltage then flows through the left front turn signal lamp feed circuit to the left front turn signal lamp.

Voltage for the right turn signal lamps flows through the right front turn signal switch output circuit terminal J of C216 and the right rear stop/turn lamp feed circuit terminal N of C216. Operation of the right turn signal lamp is similar to the left turn signal.

Tail/Stop/Turn Lamps

Voltage is applied when the ignition is in the RUN position through the TURN B/U Fuse in the fuse block, to the turn signal lamp flasher through circuit 141. Voltage is then applied from the turn signal lamp flasher to the turn/hazard switch assembly through the turn signal flasher output circuit. When the turn signal switch is placed in the left turn position, voltage is applied through the closed contacts of the turn signal switch to the left tail/stop/turn lamp through the left rear stop/turn lamp feed circuit. When the turn signal switch is placed in the TURN RIGHT position, voltage is applied through the closed contacts of the turn signal switch to the right tail/stop/turn lamp through the right rear stop/turn lamp feed circuit.

Hazard Lamps

Voltage is applied at all times from the STOP/HAZARD fuse 1 to the hazard lamp flasher through circuit 140. The current flow heats the timing element in the hazard lamp flasher. The voltage continuously opens and closes the hazard flasher output circuit to the turn/hazard switch and then to all the turn signal lamps and both of the turn telltale lamps. All of the turn signal lamps and both of the turn indicator lamps flash on and off.

Stop Lamps

Voltage is applied at all times from the STOP/HAZARD fuse 1 to the stop lamp/tcc switch through circuit 140. Voltage is applied from the stop lamp/tcc switch through the stop lamp feed circuit to the left and the right tail/stop lamps (Chevrolet) or the tail/stop/turn lamps (Pontiac) and the center high mounted stop lamp (CHMSL) when the brake pedal is depressed.

Exterior Lights Circuit Description Japan, Europe, Scandinavia

Daytime Running Lamps (Scandinavia)

When the ignition switch is turned to the RUN position, voltage is supplied from the TURN B/U Fuse 2 through circuit 141 to the headlamp switch and the DRL relay. Through the headlamp switch, voltage is applied when the ignition switch is in the RUN position through the park lamp feed circuit to the exterior lights. The left positioning lamp, the license lamps, the right side marker lamp, the taillamps, and the tail/stop lamps turn on and stay on.

License, Tail, Tail/Stop Lamps

Whenever the park lamps or the headlamps are on, voltage is applied from the TAIL LPS fuse 5 through the headlamp switch and the park lamp feed circuit to the license lamps, the tail lamps, the tail/stop/turn lamps, the left positioning lamp (Europe), the right side marker lamp, and the park/turn lamps (Japan).

Turn Signal Lamps

Voltage is applied from the TURN B/U fuse 2 to the turn signal lamp flasher through circuit 141 when the ignition switch is in the RUN position. Current flow heats the timing element in the turn signal lamp flasher causing the timing element to continuously open and close. When the turn signal switch is moved to the turn left position, voltage is applied to the left front turn signal lamp feed circuit (Europe) or the left park lamp feed circuit (Japan) and the left rear stop/turn lamp feed circuit.

Voltage flows through the left front turn signal lamp feed circuit to the instrument cluster for the left turn indicator, to the side marker lamp, to the park/turn lamp, and to the tail/stop/turn lamp (Japan).

Voltage also flows through the left rear stop/turn lamp feed circuit to the left tail/stop/turn lamp (Europe) or through the left park lamp feed circuit to the park/turn lamp (Japan). Voltage for the right turn signal lamps flows through the right front turn signal lamp feed circuit (Europe) or the right park lamp feed circuit (Japan) and the right rear stop/turn lamp feed circuit. Operation of the right turn signal is similar to that of the left turn signal.

Tail/Stop/Turn Lamps

Voltage is applied when the ignition is in the RUN position through the TURN B/U Fuse 2 to the turn signal lamp flasher through circuit 141. Voltage is then applied from the flasher to the turn/hazard switch assembly through the turn signal flasher output circuit. When the turn signal switch is placed in the left turn position, voltage is applied through the closed contacts of the turn signal switch to the left tail/stop/turn lamp through the left rear stop/turn lamp feed circuit (Europe) or through the left front turn signal lamp feed circuit (Japan). When the turn signal switch is placed in the right turn position, voltage is applied through the closed contacts of the turn signal switch to the right tail/stop/turn lamp through the right rear stop/turn lamp feed circuit (Europe) or the right front turn signal lamp feed circuit (Japan).

Hazard Lamps

Voltage is applied at all times from the STOP/HAZARD fuse 1 to the hazard lamp flasher through circuit 140. The current flow heats the timing element in the hazard lamp flasher. The voltage continuously opens and closes the hazard flasher output circuit to the turn/hazard switch assembly and then to the side marker lamps, the park/turn lamps, and the tail/stop/turn lamps and both of the turn signal indicator lamps in the instrument cluster. All of the turn signal lamps and both of the turn telltale lamps flash on and off.

Stop Lamps

Voltage is applied at all times from the STOP/HAZARD fuse 1 to the stop lamp/tcc switch through circuit 140. Voltage is applied from the stop lamp/tcc switch through the stop lamp feed circuit to turn on the left and right tail/stop lamps and the center high mounted stop lamp (CHMSL) when the brake pedal is depressed.