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8A - 8
AUDIO/VIDEO
REMOTE SWITCHES (Continued)
The two remote radio switch units share a common
steering wheel wire harness with the vehicle speed
control switches. The steering wheel wire harness is
connected to the instrument panel wire harness
through the clockspring.
OPERATION
The six switches in the two remote radio switch
units
are
normally
momentary switches that are hard wired to the Body
Control Module (BCM) through the clockspring. The
BCM sends a five volt reference signal to both switch
units on one circuit, and senses the status of all of
the switches by reading the voltage drop on a second
circuit.
When the BCM senses an input (voltage drop) from
any one of the remote radio switches, it sends the
proper switch status messages on the Programmable
Communication Interface (PCI) data bus network to
the radio receiver. The electronic circuitry within the
radio receiver is programmed to respond to these
remote radio switch status messages by adjusting the
radio settings as requested. For diagnosis of the
BCM or the PCI data bus, the use of a DRB III scan
tool and the proper Body Diagnostic Procedures man-
ual are recommended.
DIAGNOSIS AND TESTING - REMOTE
SWITCHES
Any diagnosis of the Audio system should
begin with the use of the DRB III
tool. For information on the use of the DRB
III , refer to the appropriate Diagnostic Service
Manual.
Refer to the appropriate wiring information. The
wiring information includes wiring diagrams, proper
wire and connector repair procedures, details of wire
harness routing and retention, connector pin-out
information and location views for the various wire
harness connectors, splices and grounds.
WARNING:
DISABLE
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, SEAT BELT TENSIONER, SIDE
AIRBAG, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
open,
resistor
multiplexed
diagnostic
THE
AIRBAG
SYSTEM
(1) Disconnect and isolate the battery negative
cable. Remove the remote radio switch(es) (Fig. 5)
from the steering wheel.
Fig. 5 REMOTE RADIO SWITCHES
1 - BLACK (LEFT) SWITCH
2 - WHITE (RIGHT) SWITCH
(2) Use an ohmmeter to check the switch resis-
tances as shown in the Remote Radio Switch Test
table. If the remote radio switch resistances check
OK, go to Step 3. If not OK, replace the faulty
switch.
REMOTE RADIO SWITCH TEST
Switch
Switch Position
Right
Volume Up
(White)
Right
Volume Down
(White)
Right
Mode Advance
(White)
Left
Seek Up
(Black)
Left
Seek Down
(Black)
Left
Pre-Set Station
(Black)
Advance
(3) Reconnect the battery negative cable. Turn the
ignition switch to the ON position. Check for 5 volts
at the radio control mux circuit cavities of the steer-
ing wheel wire harness connectors for both remote
radio switches. If OK, go to Step 4. If not OK, repair
the open or shorted radio control mux circuit to the
Body Control Module (BCM) as required.
JR
Resistance
3.9K ohms
±5%
10K ohms ±5%
330 0hms ±5%
1.2K ohms
±5%
2.2K ohms
±5%
68K ohms ±5%
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