1993 CHEVROLET PLYMOUTH ACCLAIM wiring

REAR LEVELING DIAGNOSTIC PROCEDURES
SELF-DIAGNOSTICS
A self-diagnostic procedure is available for the ser-
vice technician to use to detect system malfunctions.
BEFORE DIAGNOSTICS TEST
Check the 20 amp fuse (position W40) and the 30
amp circuit breaker (position W5) to be assured they
are functional components. Check all connectors that link the system into the
main body wiring harness. These include compressor,
height sensor, control module, (Fig. 7) and relay.
Also check the underbody to in trunk and leveling
harness to main body harness connectors. Also, check
all air lines, connectors, and other components for
correct installation.
TEST LAMP PIN OPERATION
The monitor lamp pin output will be activated (test
lamp on) if the detection of abnormal system opera-
tion is determined by the CM.
AFTER COMPLETION OF REPAIRS
To initiate diagnostics, disconnect the test ground
wire then reconnect for repair verification.
TERMINATION OF SELF-DIAGNOSTICS
The self-diagnostic operation is terminated when
any of the following takes place:
² Disconnecting the diagnostic input from the
ground circuit.
² Turn the ignition switch to the off position.
When the self-diagnostic operation is terminated.
The control module resumes normal operation unless
it ceases operation. Due to it detecting a system mal-
function.
TEST WEIGHT
Weight between 275-300 lbs. must be added to rear
of vehicle before diagnostic testing begins.
DIAGNOSTICS (TO START PROCESS)
(1) Remove protective connector cover from diag-
nostic connector. (2) Insert wire into diagnostic ground pin. Then at-
tach to compressor ground pin, or as an alternate, in-
sert wire into diagnostic ground pin. Then ground
other end of test wire to body structure or a control
module fastener.
IGNITION
The following self diagnostic operation is initiated
by connecting the diagnostic ground pin to ground af-
ter ignition switch is turned ON. A monitor lamp
must be connected between the Test Lamp Ground
Pin and the Test Lamp Feed Pin to display the con-
trol module diagnostics status. See (Fig. 8) for diag-
nostic test pin locations.
OPERATION
(1) The compressor relay output. From the control
module (CM), is activated until the vehicle is in the
high position. The maximum relay output operation
time is 150 610 seconds. If the expected position is
not obtained, the CM ceases self-diagnostics and any
further operation. (I.e. neither operates the compres-
sor relay or exhaust outputs). The monitor lamp out-
put is continuously activated until ignition is cycled
from OFF to ON or 60 61 minutes has elapsed after
ignition was turned off. See Diagnostics Chart 1. (2) The monitor lamp output should flash to indi-
cate the position of the height sensor. The sensor
should be in the high position. A continuously
lighted monitor lamp will indicate a system failure.
Such as the compressor relay output has operated for
150 610 seconds but the height sensor did not move
to the high position within the right shock absorber).
See Diagnostic Chart 1. (3) Next the exhaust solenoid output is activated
until the vehicle is in the low position. The maxi-
mum exhaust solenoid operation time is 120 610 sec-
onds. If the expected position is not obtained, the
module ceases self-diagnostics and any further oper-
ation. The monitor lamp output is lighted continu-
ously until ignition is cycled from OFF to ON or 60
6 1 minutes has elapsed after ignition is turned off.
See Diagnostic Chart 4. (4) The monitor lamp should flash to indicate the
height sensor is in the low position. A continuouslyFig. 7 Control Module Connector
Fig. 8 Diagnostic Test Pin Location
Ä SUSPENSION AND DRIVESHAFTS 2 - 65

CONTROL MODULE
REMOVAL
(1) Disconnect negative battery cable.
(2) Remove right side trunk trim panel.
(3) Remove electrical connectors from control mod-
ule and relay (Fig. 9). (4) Remove control module mounting screws and
remove assembly.
INSTALLATION
(1) Install relay on the control module mounting
bracket (if required). (2) Place control module in mounting position.
(3) Install mounting screws and tighten to 2-3 N Im
(19-29 in. lbs.). (4) Install control module and relay wiring connec-
tors (Fig. 9). (5) Install right side trunk trim panel.
(6) Connect negative battery cable.
COMPRESSOR RELAY
REMOVAL
(1) Remove right side trunk trim panel.
(2) Remove electrical connector from relay.
(3) Remove relay from control module mounting
bracket by prying out on locating clip (Fig. 10).
INSTALLATION
(1) Push relay onto bracket (relay will Lock into
position). (2) Install electrical connector.
(3) Install trim panel.
RIGHT SHOCK ABSORBER (WITH HEIGHT
SENSOR)
REMOVAL
(1) Disconnect negative battery cable.
(2) Raise vehicle, see Hoisting, Group 0.
(3) Remove tire assembly.
(4) Disconnect height sensor connector, located on
right rear frame rail. (5) Remove both air lines connected to shock ab-
sorber ports. (6) Remove shock, see Shock Absorbers, Removal.
INSTALLATION
(1) Install shock assembly, see Shock Absorbers,
Installation. (2) Route height sensor wire through clip on shock
bracket, then tie strap to fuel filler tube. (3) Snap height sensor connector into underbody
harness connector. (4) Insert air lines.
(5) Install wheel/tire assembly.
Fig. 9 Control Module and Relay Wiring
Fig. 10 Control Module Connector
2 - 72 SUSPENSION AND DRIVESHAFTS Ä

AUTOMATIC AIR SUSPENSION INDEX
page page
Air Lines ............................... 75
Air Springs Rear ......................... 87
Compressor Performance Test .............. 77
Diagnosis .............................. 78
General Information ....................... 73
Recharge Air Spring ...................... 87 Right Shock Absorber (With Height Sensor)
.... 88
Safety Concerns ......................... 78
Service Procedures ....................... 85
Shipping Mode .......................... 78
Solenoids (Struts and Air Springs) ............ 86
System Operation ........................ 78
GENERAL INFORMATION
This system provides automatic height control and
low spring rates to improve suspension characteristics
of the vehicle. And it will automatically level the front
and rear of the vehicle. It will also maintain the opti-
mum vehicle attitude from one passenger through full
vehicle load.
The automatic air suspension system includes the
following components:
² Compressor/air dryer assembly
² Compressor relay
² Front struts
² Rear springs
² Rear shocks
² Control module
² Air lines ²
Compressor
² Rear height sensor
² Wiring harness assembly
² Compressor cover
Front springs (and height sensors) are integral with
the shock absorber strut assemblies. While rear air
springs replace conventional steel units. Rear height is
controlled via a height sensor contained within the
right rear shock absorber. Solenoids (integral with each
air spring) control air volume/pressure requirements.
Pressurized air is distributed from the air compressor/
dryer assembly and routed to each air spring by four
separate air lines. The air lines start at the dryer and
terminate at the individual air springs. The system is
monitored and controlled by the Air Suspension Control
Module (ASCM) (Fig. 1).
Fig. 1 Automatic Air Suspension
Ä SUSPENSION AND DRIVESHAFTS 2 - 73

AIR LINE FITTINGS
To remove an air supply line from an air compres-
sor assembly air line fitting. Push in (toward re-
ceiver dryer) on the plastic ring of the receiver dryer
air supply air line fitting. While holding in the air
line fitting on the receiver dryer pull the air supply
line strait out of the fitting (Fig. 6).
The fitting has a unique push-in feature. A brass
type collet locks the air line in place. One rubber
O-Ring seals the air line to prevent air leakage. To
attach air line, just push into fitting (Fig. 7).
AIR CHECK, RESIDUAL
The air dryer has a valving arrangement that
maintains 172 to 276 kPa (25 to 40 psi). To test this function, perform the following proce-
dure: (1) Remove the air line from the dryer and strut or
spring. Attach a piece of bulk nylon tubing to one
side of a Pressure Gauge (0-300 psi), and to the strut/
spring solenoid (Fig. 8). (2) Attach another piece of nylon tubing from the
dryer (compressor) to other side of the pressure
gauge. A compression ball sleeve nut and sleeve for 3/16
inch tubing with ball sleeve connector and an inter-
nal pipe T-fitting. Can be used to attach the tubing
to the pressure gauge. (3) Activate compressor by grounding pin 508 to
pin x 20 (See Control Module Connector), cycle unit
and read actual air pressure. Pressure of 172 to 276
kPa (25 to 40 psi) indicates that the system and com-
pressor is acceptable.
COMPRESSOR PERFORMANCE TEST
This test can be performed on the vehicle to evalu-
ate compressor current draw, pressure output, and
leak down. (1) Disconnect the compressor motor wiring har-
ness connector. (2) Disconnect air line between dryer and strut or
spring solenoid. (3) Connect an air pressure gauge into the system
(Fig. 8). (4) Connect an ammeter in series between the red
wire terminal on compressor connector and a 12 volt
power source. Also, connect a ground wire from the
black wire terminal on the compressor connector to a
good ground on the frame (Fig. 9) (5) If the current draw to the compressor motor ex-
ceeds 30 amperes, replace the compressor assembly.
AIR LEAK CHECK
(1) Check all air line to connector joints.
² Air line to compressor connectors.
² Air line to solenoid.
(2) Check the rubber membranes.
² Front struts.
² Rear springs.
Fig. 6 Release Air Line from Fitting
Fig. 7 Push Air Line into Fitting
Fig. 8 Pressure Gauge Installed in System
Ä SUSPENSION AND DRIVESHAFTS 2 - 77

(2) Check all connectors for correct assembly. Check
all connectors for incorrectly installed termi-
nals. (3) Check pin #21 for minimum of 9.5 volts.
(4) Check pin #20 for minimum of 9.5 volts (with
ignition key on). (5) Check voltage at pins #5 and #16. The measure-
ment should exceed 0 volts. (6) Check pin #19 for continuity.
(7) The engine speed should exceed 680 rpm during
idle. All doors and trunk must be closed for the
system to function.
DIAGNOSTICS PROCEDURES
(1) Use the D.R.B. II tester and the 1991 air suspen-
sion diagnostic service cartridge to begin the trouble-
shooting process. (2) Use the D.R.B. mating connector under the dash
(drivers side) to plug-in the D.R.B. II test connector
(Fig. 10). (3) The tester will conduct a complete check of the
suspension system status. (4) The tester will list the steps to follow to access
and diagnose the failure. (5) A Volt/Ohm meter can be used for some diagnos-
tic testing.
HEIGHT SENSOR CHECK
If a sensor signal/signals are missing. Follow the
repair procedure listed below. (1) Check ground circuit continuity. (Remember
front and rear grounds are on different circuits. (2) For front ground circuit continuity check circuit
S 33. (3) For rear ground circuit continuity check circuit
X20. (4) Refer to control module pin out chart and wiring
diagram (see Group 8F in wiring diagram manual) for
individual circuit details. (5) If open circuits are not found replace the compo-
nent. Complete circuit testing and connector assem-
blies before replacing a strut or right rear shock. (6) To measure resistance values, see Height Sensor
Logic Chart and Initial Diagnostic Check in System
Operation.
HEIGHT SENSOR LOGIC CHART
Ä SUSPENSION AND DRIVESHAFTS 2 - 79

SERVICE PROCEDURES
CONTROL MODULE (ASCM)
REMOVAL (1) Disconnect negative battery cable.
(2) Remove right side trunk trim panel.
(3) Remove electrical connectors from control mod-
ule and relay (Fig. 11). (4) Remove control module mounting screws and
remove assembly.
INSTALLATION
(1) Install relay on the control module mounting
bracket (if required). (2) Place control module in mounting position.
(3) Install mounting screws and tighten to 2-3 N Im
(19-29 in. lbs.) torque. (4) Install control module and relay wiring connec-
tors (Fig. 11). (5) Install right side trunk trim panel.
(6) Connect negative battery cable.
COMPRESSOR RELAY
REMOVAL
(1) Remove right side trunk trim panel.
(2) Remove electrical connector from relay.
(3) Remove relay from control module mounting
bracket by prying out on locating clip (Fig. 11)
INSTALLATION (1) Push relay onto bracket (relay will Lock into
position.) (2) Install electrical connector. (3) Install trim panel.
COMPRESSOR ASSEMBLY
REMOVAL
(1) Disconnect battery negative cable.
(2) Raise vehicle, see Hoisting, Group 0.
(3) Remove cover from compressor assembly. Re-
move air hose (see AIR LINES) and electrical connec-
tors (Fig. 12) (4) Remove compressor assembly mounting screws
and lower assembly from vehicle. (5) Remove mounting bracket screws and slide
mounting bracket away from compressor.
INSTALLATION (1) Slide mounting bracket on compressor and in-
stall screws and tighten to 8 N Im (70 in. lbs.) torque.
DO NOT OVER TORQUE THESE SCREWS. (2) Install compressor assembly to frame rail and
tighten screws to 8 N Im (70 in. lbs.) torque. DO NOT
OVER TORQUE THESE SCREWS. (3) Connect air hose and electrical connector to com-
pressor assembly. (4) Install cover on compressor assembly and tighten
screws to 6 N Im (40 in. lbs.) torque.
(5) Lower vehicle and connect battery negative
cable. (6) Check operation of the system.
AIR DRYER
REMOVAL
Remove compressor assembly. See COMPRESSOR
ASSEMBLY.
Fig. 11 Control Module and Relay Wiring
Fig. 12 Compressor Assembly
Ä SUSPENSION AND DRIVESHAFTS 2 - 85

INSTALL
(1) Inspect O-Ring condition and position on sole-
noid stem. (O-Ring can become dislodged during re-
moval (Fig. 16). (2) Install solenoid with tangs to top ledge of hous-
ing and install retaining clip. (3) Reconnect air line and electrical connection.
STRUT (AIR SUSPENSION) DAMPERASSEMBLY
Service procedures for removal and installation for
(air or steel spring) assemblies are essentially the
same. Except for air venting/recharging and discon-
necting/connecting air lines and electrical connection.
REMOVAL (1) Disconnect battery negative cable.
(2) Hoist vehicle and remove wheel and tire assem-
bly. (3) See AIR LINES AND FITTINGS and discon-
nect air line. (4) Disconnect electrical leads, solenoid and height
sensors. (5) See SOLENOIDS (STRUT AND AIR SPRING)
and vent air spring and remove solenoids. (6) See STRUT DAMPER ASSEMBLY in FRONT
SUSPENSION and remove strut.
DISASSEMBLY/ASSEMBLE Disassembly is restricted to upper mount and bear-
ing housing. The strut shock absorber, air spring
with integral height sensor, solenoid and wiring har-
ness are serviced as an assembly. (1) Hold retaining plate locking washer and re-
move strut rod nut. (2) Remove locking washer, retainer plate, spacer,
flat washer and mount/bearing housing assembly
(Fig. 17). (3) Assemble in reverse order. Hold retainer plate
locking washer with suitable tool and tighten strut
rod nut to 75 N Im (55 ft. lbs.) torque.
INSTALLATION (1) See STRUT DAMPER ASSEMBLY in FRONT
SUSPENSION and install strut. (2) Install solenoid, see: SOLENOIDS (STRUT
AND AIR SPRINGS). (3) Connect electrical leads, solenoid and height
sensor. (4) Charge (inflate) air spring. See RECHARGE-
AIR SPRING to activate spring solenoid and air com-
pressor. Add air for 60 seconds.
RECHARGE AIR SPRING
To activate compressor; Ground Pin S08 to Pin
X20. To Activate Spring Solenoid:
² LF: Ground Pin S31 to X20 ²
RF: Ground Pin S30 to X20
² RR: Ground Pin S32 to X20
AIR SPRINGS REAR
REMOVAL
(1) Disconnect battery negative cable, hoist vehicle
and remove wheel and tire assembly. (2) See AIR LINES AND FITTINGS and discon-
nect air line and electrical connector from solenoid. (3) See SOLENOIDS (STRUT AND AIR SPRINGS)
and vent air from spring. Remove solenoid. (4) Release upper air spring alignment/retainer
clips. (Fig. 18) (5) Remove lower spring to axle nut (Fig. 19).
(6) Pry assembly down to pull alignment studs
through retaining clips (Fig. 20). Remove assembly.
INSTALLATION
(1) Position assembly lower stud into axle seat and
upper alignment pins through frame rail adaptor. (2) Install upper retaining clips.
(3) Install lower spring to axle nut: LOOSE AS-
SEMBLE. (4) Install solenoid and connect air line and electri-
cal connector. (5) Charge (inflate) air spring. See RECHARGING
AIR SPRING and add air for 60 seconds. (6) AFTER partial air recharge tighten lower nut
Fig. 17 Air Strut Upper Mount Assembly
Ä SUSPENSION AND DRIVESHAFTS 2 - 87

to 68 N Im (50 ft. lbs.) torque.
(7) Install wheel and tire assembly. Lower vehicle,
install wheel and tire assembly and connect battery
negative cable.
RIGHT SHOCK ABSORBER (WITH HEIGHT
SENSOR)
REMOVAL
(1) Disconnect battery negative cable.
(2) Raise vehicle, see Hoisting, Group 0.
(3) Remove tire assembly.
(4) Disconnect height sensor connector located on
right rear frame rail. (5) Remove shock, see Shock Absorbers, Removal.
INSTALLATION
(1) Install shock assembly, see Shock Absorbers,
Installation. (2) Route height sensor wire through retaining
clips and then tie strap to fuel filler tube. (3) Snap height sensor connector into underbody
harness connector. (4) Install wheel/tire assembly.
(5) Height sensor wiring harness and white paint
mark on bottom shock eye must face to the front of
the vehicle (Fig. 21).
Fig. 18 Release Retaining Clips
Fig. 19 Remove/Install Lower Spring to Axle Nut
Fig. 20 Pry Assembly Out of Retaining Clips
Fig. 21 Right Rear Shock Absorber Installation
2 - 88 SUSPENSION AND DRIVESHAFTS Ä