Cruise Control - GMC G Service Manual

SUBJECT
Cruise Control..............................................................................................................................................................9- 1
Description................................................................................................................................................................9- 1
Diagnosis of Cruise Control System......................................................................................................................... 9- 4
On-Vehicle Service....................................................................................................................................................... 9- 8
Vacuum Release Valve Replacement.....................................................................................................................9- 8
Clutch Release Switch Replacement......................................................................................................................9- 8
Cruise Control Module Replacement......................................................................................................................9- 9
Multi-Function Switch Replacement........................................................................................................................9-10
Servo Replacement.................................................................................................................................................. 9-10
Radio ........................................................................................................................................................................... 9-15
Description................................................................................................................................................................9-15
Diagnosis.....................................................................................................................................................................9-15
Chart 1 - System Diagnosis and Analysis...........................................................................................................9-16
Chart 2 - Noisy Part 1 ........................................................................................................................................... 9-17
Chart 3 - Noisy Part 2 ........................................................................................................................................... 9-18
Chart 4 - ECM or Digital Dash Noise...................................................................................................................9-19
Chart 5 - Ignition Noise......................................................................................................................................... 9-20
Chart 6 - Antenna Noise....................................................................................................................................... 9-21
Chart 7 - Weak........................................................................................................................................................ 9-22
Chart 8 - Alternator Whine.................................................................................................................................... 9-23
Chart 9 - Dead........................................................................................................................................................ 9-24
Chart 10 - Tape....................................................................................................................................................... 9-25
Accessory Noise....................................................................................................................................................... 9-26
Diagnostic RF Sniffer............................................................................................................................................... 9-28
Radio On-Vehicle Service........................................................................................................................................... 9-29
Radio Receiver Replacement.................................................................................................................................. 9-29
Antenna Replacement.............................................................................................................................................. 9-29
Speaker Replacement.............................................................................................................................................. 9-31
DESCRIPTION
Cruise control is a speed control system which maintains
a desired vehicle speed under normal driving conditions.
However, steep grades up or down may cause variations in
the selected speeds. The electronic cruise control system
has the capability to cruise coast, resume speed, acceler­
ate, and "tap-up" and "tap-down" (figure 1).
SECTION 9
ACCESSORIES
CONTENTS

CRUISE CONTROL

2 1. Set/Coast Switch
2. Off/On/Resume/Accel Switch
3. Directional Signal Lever
Figure 1 - Multi-Function Lever
9-1
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