The IP and related parts form a rigid structure. This structure encloses and supports many components on or near the passenger compartment side of the cowl. The top of the IP is attached to the front of dash, along the base of the windshield by bolts. The IP is also attached at both outer lower corners by nuts. The bottom of the IP is attached to a stamped metal tie bar. The tie bar adds to the rigidity of the IP structure. Sound insulator panels are attached to the bottom of the IP. The sound insulator panels conceal the components under the IP and also provides a finished appearance.

The steering column is clamped in place at the left side of the IP. Below the steering column is an IP driver knee bolster. An impact-absorbing pad covers the top of the IP. Trim covers and trim plates accent the appearance of the exposed rear face of the IP.

The air conditioning module case is attached to the front of dash. Air ducts connect the case outlets to the following outlets:

A high level air outlet is provided at each end of the IP. The air conditioning module and the ducts are concealed within the IP structure.

All Chevrolet and Canadian Pontiac and Chevrolet vehicles are equipped with daytime running lamps. These vehicles are equipped with a headlamp automatic control ambient light sensor. The sensor is installed flush with the top surface of the IP upper trim panel, under the windshield defroster nozzle grille.

Vehicles equipped with the theft deterrent system have a security LED. The LED is installed flush with the top surface of the IP upper trim panel, under the windshield defroster nozzle grille.

The IP wiring harness is installed behind the IP area.

The headlamp and instrument panel lamp dimmer switch with thumbwheel dimmer control is mounted in the IP to the left of the instrument cluster

The headlamp switch controls the following lamps:

The dimmer control regulates the intensity of the IP illumination.

On Chevrolet vehicles equipped with fog lamps, the front fog lamp switch is next to the headlamp and the IP lamp dimmer switch. On Pontiac vehicles equipped with fog lamps, the front fog lamp switch will be below the headlamp and IP lamp dimmer switch.

Perform the following steps in order to use the front fog lamps:

1. Turn on the headlamps or the parking lamps.
2. Push the right side of the front fog lamp switch.

This action will turn on the front fog lamps.

3. Push the left side of the switch.

This action will turn off the front fog lamps.

Do not use the front fog lamps as a substitute for the headlamps. Switching to high-beam headlamps will turn off the front fog lamps. Switching back to low-beam headlamps will turn the front fog lamps on again.

On Chevrolet vehicles equipped with rear fog lamps, the switch is located on the IP accessory trim plate. The switch will be in either the second or third position, depending on option content.

The rear compartment lid release switch releases the rear deck lid of the vehicle automatically.

On Chevrolet vehicles, the rear compartment lid release switch is located in the glove box. On Pontiac vehicles, the rear compartment lid release switch is located on the left side of the IP, below the headlamp and the IP lamp dimmer switch and the fog lamps switch.

The rear defogger switch, when activated, slowly heats the rear window in order to remove interior fog or outside snow and ice. The switch has an integral lamp. The switch will operate for 5 or 10 minutes, depending on the following conditions:

The switch will automatically turn off or may be turned off as follows:

The rear defogger switch is located with the heating ventilation and air conditioning (HVAC) controls

The DRL ambient light sensor is located to the right of the heat and air conditioning duct, in the center of the IP.

As the intensity of the light reaching the sensor increases, the electrical resistance of the sensor decreases. When the DRL control module senses a low resistance in the sensor, the module allows voltage to be applied to the DRL diode and then to the headlamps. Due to the voltage drop across the diode, the headlamps are on at a reduced intensity.

As the intensity of light reaching the sensor decreases, the electrical resistance of the sensor increases. When the DRL module senses a high resistance in the sensor, the module closes an internal relay and allows the headlamps to come to full intensity.