Steering Wheel Controls System Circuit Description; Power Antenna System Description; Power Antenna System Circuit Description; Special Tools And Equipment - GMC Chevrolet Camaro 1998 Service Manual

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Body and Accessories
Steering Wheel Controls System Circuit
Description
Steering Wheel Radio Control Switches
The steering wheel control switches control the
following radio features:
• Radio power
• The volume
• The station frequency
Voltage is supplied to the RH steering wheel controls
through the RADIO Fuse 3, circuit 243, the SIR
coil assembly when the ignition switch is in ACCY,
RUN or the RAP mode is active. The switch.es are a
ladder network consisting of the switches and a
series of resistors. The ladder network allows each
switch to have a different resistance. The different
resistances allow a different voltage output to the radio
for each switch pressed.
Voltage is supplied to both steering wheel controls
through the RADIO Fuse 13, circuit 1458, through the
SIR coil assembly. Ground is supplied to both
steering wheel controls from G200, circuit 650 through
the SIR coil assembly. The steering wheel control
(SWC) switches use incandescent backlighting. The
illumination signal circuit 1458 is a pulse width
modulated (PWM) signal from the headlight switch.
The bulbs are serviceable.
SIR Coil Assembly
The SIR Coil Assembly contains 6 wires, four of which
are used by the SWC. The SWC allows voltage to
be sent from the steering wheel switches to the radio
while the steering wheel is being turned.
Power Antenna System Description
The rear-mounted, telescoping, rod-type antenna fully
extends whenever the radio is in use. The antenna
retracts when the following conditions exist:
• The rc\dio is off.
• The ignition switch is in the OFF position.
• The retained accessory power (RAP) is inactive.
The antenna mast is attached to a plastic cable that is
driven up a:nd down by an electric motor. The motor
is automatically shut off by the limit switches when the
antenna reaches the full up or full down position.
Entertainment 8-281
Power Antenna System Circuit Description
When the radio is turned on voltage is applied from
the radio (circuit 314) to the radio power antenna ,.
internal relay coil. The relay contacts close, and battery
voltage is applied to the motor. Terminal B of the .
motor is grounded through the UP switch and the relay
contacts. The motor drives the antenna mast up.
When the antenna is at its full height, the UP switch
opens and the motor stops.
When the radio or ignition switch is turned off, voltage
is removed from the relay coil. The relay contacts
open, applying battery voltage to the motor. The motor
terminal A is now grounded. The DOWN switch at
the antenna now has voltage applied through the relay,
the voltage of the motor has reversed polarity. It
runs in the opposite direction, retracting the
antenna mast.
At the end of the antenna's travel, the DOWN switch
opens and breaks the current flow. Both sets of
switches are now in the places shown in the
schematic, the radio is off and the antenna mast
is down.
The antenna is connected to the radio by
coaxial cable.
Special Tools and Equipment
Illustration
Tool Number/ Description
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J 39916-A
Delco Audio System
Diagnostic Kit
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65874