Radio, Stereo, and Compact Disc: Description and Operation

Important:
^ For Delco-Loc II Anti-theft Feature (available only on Chevy UIT Disk Radio option) or for Radio Features and Controls Operation.
^ For Theft-Loc Anti-theft Feature (available on all Pontiac Radio Options UT6, UP3 and UN6) or Radio Features and Controls Operation.
The Radio receives battery voltage at all times on CKT 40 from Fuse 8 to keep clock and preset station memory alive when the Ignition is "OFF." With the Ignition Switch in "ACCY", "RUN" or "RETAINED ACCESSORY POWER (RAP)," voltage is applied to CKT 43 from Fuse 17 to enable Radio operation.

When the Park Lights or Headlights are turned "ON," voltage is applied to the Radio on CKT 9 from the Headlight Switch. When voltage is applied to CKT 9 at the Radio, the Radio will illuminate the display. With the Headlights or Park Lights "ON," the Radio display may be dimmed manually using the I/P Dimmer Switch. The I/P Dimmer Switch varies the voltage on CKT 8 to the Radio to control display dimming.

Speakers: BASE (UQO OR U62)
With the Base Speaker System, the audio signals are amplified within the Radio, and the outputs go directly to the speakers.

Speakers: DELCO-BOSE�
The Delco-Bose� Music System uses a relay to control Battery voltage to three speaker/amps within the Passenger Compartment. A shielded cable carries the audio signals from the Radio to the speaker/amps where the signals are then amplified to drive speakers.

Speakers: UW2 (10 SPEAKER SOUND SYSTEM)
For eight of the systems ten speakers, the audio signals are amplified within the Radio and the outputs go directly to the speakers.

The Amplifier is used to drive two subwoofers. The Amplifier receives all the amplified signals coming from the Radio. These signals are used to determine the Amplifier's output to the subwoofers The Amplifier has separate power and ground inputs and is turned "ON" and "OFF" from the control output of the Radio on CKT 314.

Steering Wheel Radio Control Switches
The Steering Wheel Control switches control radio power, volume and station frequency. These switches are actually a ladder network consisting of the switches and a series of resistors. The ladder network is arranged so that each switch has a different resistance. This allows a different voltage output to the radio for each switch pressed.

The steering wheel control (SWC) switches use incandescent backlighting. The illumination signals CKT 8 is a pulse width modulated (PWM) signal from the headlight switch. The bulbs are serviceable.

SIR Coil Assembly
The SIR Coil Assembly contains four wires used by the Steering Wheel Controls. This allows voltage to be sent from the Steering Wheel Switches to the Radio while the Steering Wheel is being turned.