1999 CHEVROLET ASTRO relay

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6-62
Fuse/Circuit
BreakerUsage
1 Stop/Turn/Hazard Lamps,
CHMSL, Chime Module
2 Heated Mirror (Not Used)
3 Courtesy Lamps, Power Outside
Mirrors, Glove Box Lamp,
Dome Reading Lamps,
Vanity Mirror LampsFuse/Circuit
BreakerUsage
4 DRL Relay, DRL Module, Chime
Headlamp Switch, Keyless Entry,
Cluster, Overhead Console,
Interior Lamps Module
5 Rear Defogger
6 Cruise Module, Cruise Control
Switch, Electrochromic Mirror
7 Power Outlets, DLC, Subwoofer
Amplifier
8 Starter Enable Relay
9 License Plate Lamp, Taillamps,
Parking Lamps, Ashtray Lamp,
Panel Lights, Trailer Taillamps,
Front and Rear Sidemarker
Lamps, Door Switch Illumination,
Headlamp Switch Illumination,
Rear Seat Audio Illumination
10 Air Bag System
11 Wiper Motor, Washer Pump,
Upfitter Relay Coil

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6-63
Fuse/Circuit
BreakerUsage
12 L, M1, M2 Blower Motor, Rear
A/C Relay Coil, Front Cont.
Temp. Door Motor, HI Blower
Relay, Defogger Timer Coil
13 Cigarette Lighter, Door Lock
Switches, Dutch Door
Release Module
14 Cluster Illum, HVAC Controls,
Chime Module, Radio
Illumination, Rear Heat Switch
Illumination, Rear Wiper/Washer
Switch Illumination, Rear Liftgate
Switch Illumination, Remote
Cassette Illumination,
O/H Console
15 DRL Lamps
16 Front Turn Signals, Rear Turn
Signals, Trailer Turn Signals,
Back
-up Lamps, BTSI Solenoid
17 Radio: ATC (Standby),
2000 Series (Main Feed),
Rear Seat Audio ControlsFuse/Circuit
BreakerUsage
18 VCM
-Ign 3, VCM-Brake, 4WAL,
Cruise Stepper Motor Signal
19 Radio: ATC (Main Feed),
2000 Series (Standby)
20 PRNDL/ Odometer, TCC Enable
and PWM Solenoid, Shift A
and Shift B Solenoids,
3
-2 Downshift Solenoid
21 Security
22 Not Used
23 Rear Wiper, Rear Washer Pump
24 Not Used
A (Circuit Breaker) Power Door
Lock Relay, 6
-way Power Seat,
Remote Control Door Lock
Receiver, Dutch Door Module,
Dutch Door Release
B (Circuit Breaker) Power Windows

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6-64
Underhood Electrical Center
The underhood electrical center is located toward the
rear of the engine compartment on the driver's side.
Lift the hood and open the cover to gain access to this
fuse block.Feed Usage
AUX B Upfitter Battery Feed
AUX A Upfitter Accessory Feed
Relay
A/C Relay (Rear Heat and A/C)
Upfitter
-ACCY Relay
Starter Enable Relay
A/C Enable Relay
Fuel Pump Relay

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6-65
Fuse/Circuit
Breaker Usage
UPFITTER
-BATT Upfitter Battery Power Stud,
Trailer Wiring Harness
UPFITTER
-ACCY Upfitter Accessory Relay
Spare Not used
Fuse Puller*
Spare Not used
Spare Not used
ECM
-1B Fuel Pump Relay and Motor,
VCM, Oil Pressure
Switch/Sender
HORN Horn Relay and Horn
A/C COMP A/C Enable Relay and
Compressor
ATC Active Transfer Case
-L Van
ENG
-I Oxygen Sensors, Camshaft
Position Sensor, Mass Air Flow
Sensor, Evaporative Emission
Canister Purge Solenoid, Linear
EGR Valve Solenoid, VCM
EGR HI
IGN
-E A/C Enable Relay CoilFuse/Circuit
Breaker Usage
ECM
-I Fuel Injectors 1-6, Crankshaft
Position Sensor, VCM, Coil
Driver Module (EST)
LIGHTING Park Lamps Fuse, DRL Fuse,
Headlamp and Panel Dimmer
Switch
BATT Steering/Security Fuse, Courtesy
Fuse, ACSY CB, Stop/Hazard
Fuse, Auxiliary Power Fuse,
Cigarette Lighter Fuse, Radio
Battery Fuse
IGN A Starter Relay, Ignition Switch
IGN B Ignition Switch
ABS Electronic Brake Control
Module
A/C Blower Motor Resistor, Blower
Relay
RR HTR/AC Auxiliary Heater, A/C Relay
HTD MIR/RR
DEFOGRear Window Defogger
*A fuse puller is included in the underhood electrical
center. You will also find spare fuses.