How to adjust height on rear springs

There could be a couple of problems, first and easiest is the rear height sensor became disconnected from its mount. This is common because the sponsor clips on by a kinda weak spring and can be easily disconnected.also where the sensor mounts is a small round metal ball that screws onto frame and rear suspension, the balls after time wear to the point that the sensor spring cannot hold on.there's also an adjustment on the lower mount, if you move it up the vehicle will lower....then you could have a concern with the air compressor vent not allowing it to vent down to ride height. Or the vent solenoid on top of each bag stuck also not allowing it to vent..to ck it yourself, go for a short ride around the block and when you come back park on a level surface, shut off car, exit and close door....listen for an auditable click in the rear, and front left corner of car and watch the distance between rite and wheel lip, see if it drops. If it does I would be leaning towards the simple adjustment...also check thr front ride height on level surface, if you have a suspension problem on 1side of the car and it sits lower,it will throw off rear ride height. ...

Which ever way it steps up, usually to the right,

1. Performance
   • Suzuki has introduced slight changes to the Intruder from year to year, such as variations in accessories and styling. The bike's performance, however, has remained steadily the same. The 2004 model has a four-stroke, 1,462 cc engine with a hybrid air and liquid cooling system. The single overhead cam (SOHC) V-Twin motor generates 67 horsepower at 4,800 rpm. It has a 96 mm (3.78 inches) bore, a 101 mm (3.98 inches) stroke and has a compression ration of 8.5:1. The Intruder also has a five-speed transmission.
     
   Suspension and Brakes
   • An oil-damped, telescopic fork suspension with coil spring comprises the front suspension. A link-type, oil-damped five-way adjustable spring preload makes up the rear suspension. The front brake system uses a dual hydraulic disc, and rear uses a single hydraulic disc.
     
   • 
     
   Dimensions
   • The motorcycle has an overall length of 99.4 inches, a width of 38 inches, a height of 45.9 inches and a wheelbase of 66.9 inches. The seat sits 27.6 inches off the ground, the bike clears the ground by 5.7 inches and weighs 659 lbs.
     

on the end of each bar you will see a block with an adjusting screw in it
that screw adjusts the ride tension of the bar
screw that bolt in and the tension increases and the ride height increases
Now if the bolt is all the way in
you have to pull that block off and reposition it around 1 spline with the adjuster screwed all the way out
To that you have to jack the vehicle up and place it on jack stands
now you use stilsons with a long bar on the rod to twist it so that the block will come off
twist it further until the block goes back on 1 spline around
do the same for both sides
now screw the adjusting bolt back in and let the vehicle back down
adjust the rife height by the adjusting bolt
Not high enough
repeat the exercise and move it another spline
now for the rear
if it is coil springs , get new heavy duty springs
if leaf springs remove them and have the camber of the spring reset
then have an extra leaf added to make it stronger

Frame could be twisted from a previous wreck, the rubber isolators for the cab shell to frame could be dry rotting or in an area rusting out. Was it ever crashed- anti sway bar might reveal a twist)? Core support might be twisted. Other suspension components may be dry rotting or worn. Front tires may also be two different sizes overall.

New springs replaced pairs would be a better solution than spacers if evertything tracks back to spring height issues. You may also have some cracked leaves in the rear springs as well.

Have you checked the ride height and made those adjustments yet?

start here

The air suspension system is designed to improve ride, handling and general vehicle performance for static, on-road and off-road driving condition:

• Ride is improved by using an air type spring (the soft ride is inherent).
• Handling is improved by maintaining constant vehicle attitude.

The system consists of unique rear air springs, air compressor, air lines, air spring solenoids, height sensor, air suspension control module, attachments and associated signals derived from both driver and road inputs. With these components and signals, the air suspension control module commands changes in vehicle height that are necessary for the load leveling features.
The load leveling feature rear air suspension (RAS) systems shall automatically make adjustments in vehicle height so that the vehicle is always at trim height and constant front-to-rear vehicle attitudes are maintained over the expected load range of the vehicle. Adjustments in height that are necessary to correct height differences between the vehicle's left and right sides for RAS system shall be restricted to what can be reliably achieved with one air suspension height sensor.
The system uses one air suspension height sensor, a steering sensor, generic electronic module (GEM) transfer case inputs, and other vehicle sensors to measure driver and road inputs. The system changes vehicle height using an air compressor, two air lines, and the use of an air spring with an air spring solenoid.
The air suspension system holds vehicle height when the rear hatch or any door is opened. The system stores rear vehicle height the moment any open door is detected. The system then maintains this height regardless of the addition or removal of a load. The system will return to its commanded height when all doors are closed and the vehicle speed exceeds 16 km/h (10 mph).
Air Suspension Switch
The air suspension switch is located behind the RH kick panel on a mounting bracket. The switch interrupts power to the air suspension control module.
The air suspension switch supplies a signal to the air suspension control module. Without the air suspension control module receiving this signal the load leveling system is inoperative and will not react when rear of the vehicle is raised or lowered. If the air suspension system is disabled by turning off air suspension switch, a "CHECK SUSP" will appear in the RH corner of the instrument cluster with the ignition in the run position.
Air Compressor
The RAS air compressor:

• Is not interchangeable with four wheel air suspension (4WAS) compressor.
• Consists of the compressor and vent solenoid; neither are replaceable as individual items.
• Is mounted in the engine compartment between the washer fluid bottle and headlamp (RH front corner).
• Is a single cylinder electric motor driven unit that provides pressurized air as required.
• Is powered by a solid state relay, controlled by the air suspension control module.
• Passes pressurized air through the compressor air drier that contains silica gel (a drying agent). Moisture is then removed from the compressor air drier when vented air passes out of the system during vent operation.
• Air drier has a single port and is not interchangeable with 4WAS compressor air drier.
• Air drier may be replaced separately.
• Incorporates a snorkle that may be replaced separately.

The vent solenoid:

• Allows air to escape from the system during venting actions.
• Is located in the air compressor cylinder head.
• Has a 160 psi internal relief valve.
• Shares a common electrical connector with the air compressor motor.
• Is enclosed in the cylinder head casting, which forms an integral valve housing that allows the valve tip to enter the pressurized side of the system.
• Has an O-ring seal that prevents air leakage past the valve tip.
• Opens when the air suspension control module determines lowering is required.
• Provides an escape route for pressurized air that opens when system pressures exceed safe operating levels.
• Is replaced with the air compressor as a unit.

Air Spring
RAS vehicles use air springs in the rear. The air springs provide a varying spring rate proportional to the systems air pressure and volume. The air suspension system regulates the air pressure in each air spring by compressing and venting the system air. Increasing air pressure (compressing) raises the rear of the vehicle while decreasing air pressure (venting) lowers the rear of the vehicle. Vehicle height is maintained by the addition and removal of air in each air spring through an air spring solenoid installed in the upper spring cap and energized through the air suspension control module.
The air springs are mounted between the axle spring seats and the frame upper spring seats.
The two air springs replace the conventional rear coil springs.
Air Suspension Height Sensor
When the air suspension height sensor indicates that the rear of the vehicle is lower than trim under normal driving conditions, the air compressor will turn on and pump compressed air to the air springs. When the sensor indicates that the rear of the vehicle is raised above trim under normal driving conditions, this will cause the air to be vented from the air springs to lower the vehicle back to its trim height level.
One air suspension height sensor is mounted on the vehicle. The air suspension height sensor sends a voltage signal to the air suspension control module. The output ranges from approximately 4.75 volts at minimum height (when the vehicle is low or in full jounce), to 0.25 volts at maximum height (when the vehicle is high or in full rebound). The air suspension height sensor has a useable range of 80 mm (3 in) compared to total suspension travel of 200-250 mm (8 to 10 in) at the wheel. Therefore, the air suspension height sensor is mounted to the suspension at a point where full rear suspension travel at the wheel is relative to 80 mm of travel at the air suspension height sensor. The air suspension height sensor is attached between the No. 5 frame crossmember (upper socket) and the panhard rod (lower socket). Replace the air suspension height sensor as a unit.
Compressor Relay
The compressor relay is energized by the air suspension control module to allow high current to flow from the battery to the compressor motor.

• A solid state relay is used in the air suspension system for air compressor control. The relay incorporates a custom power metal oxide semi-conductor field effect transistor (MOSFET) and ceramic hybrid circuitry. The relay switches high current loads in response to low power signals and is controlled by the logic of the air suspension control module.

Air Suspension Control Module
NOTE: The 4WAS air suspension control module is used for the RAS system. The internal processor recognizes external circuitry to determine if it is installed in a 4WAS or a RAS equipped vehicle.
NOTE: The air suspension control module is calibrated with information from the air suspension height sensor. A new or exchanged air suspension control module requires a ride height adjustment calibration process to be performed.
The air suspension control module controls the air compressor motor (through a solid state relay), and the air spring solenoids. The air suspension control module also provides power to the air suspension height sensor. The air suspension control module controls vehicle height adjustments by monitoring the air suspension height sensor, vehicle speed, a steering sensor, acceleration input, the door ajar signal, transfer case signals, and the brake pedal position (BPP) switch. The air suspension control module also conducts all fail-safe and diagnostic strategies and contains self-test and communication software for testing of the vehicle and related components.
The air suspension control module is mounted in the passenger compartment inside the instrument panel above the radio and temperature controls.
The air suspension control module monitors and controls the air suspension system through a 32-pin two-way connector. The air suspension control module is keyed so that the air suspension control module cannot be plugged into an incorrect harness. There are two sides of the harness connection to the air suspension control module. Each is uniquely colored and keyed to prevent reversing the connections.
Air Suspension Diagnostic Connector
The air suspension diagnostic connector is used to aid the technician in diagnosing the air suspension system. It is also used to vent the system of compressed air when air suspension system components need to be repaired or replaced. The air suspension diagnostic connector is located under steering column.

maybe you got dirt in the line to the rear. Here's some background info:

The air suspension system includes the following major components:

• Air compressor to supply air to the air springs (part of front spring and shock and rear spring and shock absorber assemblies
• Front spring and shock (3C098) and rear spring and shock absorber (5A965) at each corner of the vehicle
• Four linear air suspension height sensors (5359): two rear and two front height sensors to maintain the vehicle at the proper ride height; only LH rear height sensor is used for air suspension.
• Dual-mode front spring and shock and rear shock absorber assemblies with internal actuator.

All system functions are controlled by vehicle dynamics control module (5A919). This control module receives inputs from several different sources. These inputs include:

• vehicle speed via multiplex communication network
• ignition switch position
• door position via multiplex communication network
• height sensor position
• air suspension service switch
• engine rpm via multiplex communication network
• ride and steering personality settings via multiplex communications network

Communications monitor system operation and allow diagnosis of any concerns that may develop in the system.

• System monitoring for the driver's use is provided through the instrument panel mounted message center indicator (10D898).
• Diagnosis communication for the service technician is provided through the data link connector (14489) (DLC) under the instrument panel and Rotunda New Generation Star (NGS) Tester 007-00500 or equivalent.

The message center indicator will display AIR LEVELING DISABLED or CHECK RIDE CONTROL if the suspension system is not turned on or the vehicle dynamics control module detects a concern. If air leveling system disabled is displayed, check that air suspension service switch is in the ON position.
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Weight Added When weight is added to the vehicle, the air suspension system responds as follows:

• Air suspension height sensor length is reduced from trim length, sending a "vehicle is low" signal to the vehicle dynamics control module (5A919).
• To restore vehicle to the trim position, the vehicle dynamics control module turns the compressor on by grounding the compressor relay control Circuit 420 (DB/Y). The relay is ground-side switched.
• To allow pressurized air to enter the rear spring (5560) and front spring and shock (3C098), the control module opens the solenoid valves (5311).
• Compressed air flows from the compressor, through the compressor air drier assembly, air lines and solenoid valves into the air springs.
• As the air springs raise the body height, the air suspension height sensor (5359) increases in length until the preset trim height is reached.
• The vehicle dynamics control module then turns off the compressor (through the relay) and closes the air spring solenoid valves.
• ----------------------------------------------------------------------------
• Weight Removed When weight is removed, the air suspension system responds as follows:
  
• Air suspension height sensor length is increased from the trim length, sending a "vehicle is high" signal to the control module (5A919).
• To restore the vehicle to the trim position, the vehicle dynamics control module opens the vent solenoid valve (located in the compressor assembly) and opens the solenoid valves (5311).
• Compressed air flows from air springs, through the solenoid valves, air lines, compressor air drier (5346) and out the vent solenoid valve.
• As the body lowers, the air suspension height sensor length decreases until the preset trim height is reached.
• The vehicle dynamics control module then closes the vent and solenoid valves.

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Control Module Power and Ground The vehicle dynamics control module (5A919) is located above the upper luggage compartment trim panel and lower module tray. Module power is provided by Circuit 418 (DG/Y) at Pins 36, 37, 56, 57, 58 and is powered through a Fuse 7 (30A) in power distribution box. Module ground is provided through control module wire harness Pins 6, 39, 40 and 60. The data link connector (14489) (DLC) is located in the passenger compartment under the instrument panel, 300 mm (12 inches) right of the steering column. This connector allows communications between the vehicle dynamics control module and either Rotunda New Generation Star (NGS) Tester 007-00500 or equivalent or Rotunda Service Bay Diagnostics System (SBDS)® 001-00001 or equivalent. When the CHECK RIDE CONTROL message is displayed in the message center indicator (10D898), a system error has been detected by the vehicle dynamics control module and is stored in the control module. This diagnostic trouble code (DTC) will be retained for the next 80 ignition switch cycles. If there is no repeat of the same error during these 80 ignition switch cycles, the control module will erase the DTC. Because of this self-erasing memory, a customer may have had a concern "just a few days ago" that is not retrieved from memory when Diagnostic Test Mode (DTC) "Retrieve/Clear Continuous DTCs" is executed. This must be kept in mind if you must tell customer that no current concern has been found. When the vehicle dynamics control module detects a concern, the air suspension system is disabled for the current ignition cycle. If the condition causing the concern clears up during the current ignition switch cycle, the system will not reactivate. For example, if the customer has severely overloaded the luggage compartment, the system will not be able to trim the vehicle without exceeding the compressor run time. This will generate a DTC that disables the computer controlled suspension system. If the customer then drives the vehicle and unloads the luggage compartment without turning the ignition switch OFF, the system will not adjust for the new load. The customer will experience poor ride quality and the vehicle will not adjust trim.

is switch on?
The air suspension switch and bracket is mounted below the RH side of the instrument panel.

Dealer can run diagnostic test with scan tool for fault codes.
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The air suspension system is designed to improve ride, handling and general vehicle performance for static, on-road and off-road driving conditions:

• Ride is improved by using an air type spring (the soft ride is inherent).
• Handling is improved by maintaining constant vehicle attitude.

The system consists of unique rear air springs, the air compressor, air lines, air spring solenoids, height sensor, air suspension control module, attachments and associated signals derived from both driver and road inputs. With these components and signals, the air suspension control module commands changes in vehicle height that are necessary for the load leveling features.
The load leveling feature rear air suspension (RAS) systems shall automatically make adjustments in vehicle height so that the vehicle is always at trim height and constant front-to-rear vehicle attitudes are maintained over the expected load range of the vehicle. Adjustments in height that are necessary to correct height differences between the vehicle's left and right sides for the RAS system shall be restricted to what can be reliably achieved with one air suspension height sensor.
The system uses one air suspension height sensor, a steering sensor, generic electronic module (GEM) and other vehicle sensors to measure driver and road inputs. The system changes vehicle height using an air compressor, two air lines and the use of air springs with air spring solenoids.
The air suspension system holds vehicle height when the rear hatch or any door is opened. The system stores rear vehicle height the moment any open door is detected. The system then maintains this height regardless of the addition or removal of a load. The system will return to its commanded height when all doors are closed or the vehicle speed exceeds 16 km/h (10 mph).
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Air Spring
RAS vehicles use air springs in the rear. The air springs provide a varying spring rate proportional to the systems air pressure and volume. The air suspension system regulates the air pressure in each air spring by compressing and venting the system air. Increasing air pressure (compressing) raises the rear of the vehicle while decreasing air pressure (venting) lowers the rear of the vehicle. Vehicle height is maintained by the addition and removal of air in each air spring through an air spring solenoid installed in the upper spring cap and energized through the air suspension control module.
The two air springs support the conventional rear leaf coil springs.
Air Suspension Height Sensor
One air suspension height sensor is mounted on the vehicle. The air suspension height sensor sends a voltage signal to the air suspension control module. The output ranges from approximately 4.75 volts at minimum height (when the vehicle is low or in full jounce), to 0.25 volts at maximum height (when the vehicle is high or in full rebound). The air suspension height sensor has a useable range of 80 mm (3.2 in) compared to total suspension travel of 200-250 mm (8 to 10 in) at the wheel. Therefore, the air suspension height sensor is mounted to the suspension at a point where full rear suspension travel at the wheel is relative to 80 mm (3.2 in) of travel at the air suspension height sensor. The air suspension height sensor is attached between the No. 5 frame crossmember (upper socket) and the panhard rod (lower socket).
When the air suspension height sensor indicates that the rear of the vehicle is lower than trim under normal driving conditions, the air compressor will turn on and pump compressed air to the air springs. When the sensor indicates that the rear of the vehicle is raised above trim under normal driving conditions, this will cause the air to be vented from the air springs to lower the vehicle back to its trim height level.
Compressor Relay
The compressor relay is energized by the air suspension control module to allow high current to flow from the battery to the compressor motor.

• A solid state relay is used in the air suspension system for air compressor control. The relay incorporates a custom power metal oxide semi-conductor field effect transistor (MOSFET) and ceramic hybrid circuitry. The relay switches high current loads in response to low power signals and is controlled by the logic of the air suspension control module.

Air Suspension Control Module
NOTE: The 4WAS air suspension control module is used for the RAS system. The internal processor recognizes external circuitry to determine if it is installed in a 4WAS or a RAS equipped vehicle.
NOTE: The air suspension control module is calibrated with information from the air suspension height sensor. A new or exchanged air suspension control module requires a ride height adjustment calibration process to be performed.
The air suspension control module controls the air compressor motor (through a solid state relay), and the air spring solenoids. The air suspension control module also provides power to the air suspension height sensor. The air suspension control module controls vehicle height adjustments by monitoring the air suspension height sensor, vehicle speed, a steering sensor, acceleration input, the door ajar signal, transfer case signals, and the brake pedal position (BPP) switch. The air suspension control module also conducts all fail-safe and diagnostic strategies and contains self-test and communication software for testing the vehicle and related components.
The air suspension control module monitors and controls the air suspension system through a 32-pin two-way connector. The air suspension control module is keyed so that the air suspension control module cannot be plugged into an incorrect harness. There are two sides of the harness connection to the air suspension control module. Each is uniquely colored and keyed to prevent reversing the connections.
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Visual Inspection Chart Mechanical Electrical

• Restricted suspension movement
• Excessive vehicle load
• Cut, severed or crimped air line(s)
• Unmounted height sensor
• Damaged air spring(s)

• Open fuses:
  • Central junction box (CJB) Fuse 4 (15A), 6 (5A) and 20 (5A)
  • Battery junction box (BJB) Fuse 109 (50A)
• Loose, corroded or disconnected connectors
• Air suspension switch is in the OFF position
• Damaged solenoid valve(s)

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• The compressor is inoperative

• BJB Fuse 109 (50A).
• Air compressor assembly.
• Circuitry.
• Air suspension relay.

do you have just rear air suspension? here's rear only. 4 wheel different. Deler an run a diagnostic test with WDS machine and get fault codes.
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The air suspension system is designed to improve ride, handling and general vehicle performance for static, on-road and off-road driving conditions:

• Ride is improved by using an air type spring (the soft ride is inherent).
• Handling is improved by maintaining constant vehicle attitude.

The system consists of unique rear air springs, the air compressor, air lines, air spring solenoids, height sensor, air suspension control module, attachments and associated signals derived from both driver and road inputs. With these components and signals, the air suspension control module commands changes in vehicle height that are necessary for the load leveling features.
The load leveling feature rear air suspension (RAS) systems shall automatically make adjustments in vehicle height so that the vehicle is always at trim height and constant front-to-rear vehicle attitudes are maintained over the expected load range of the vehicle. Adjustments in height that are necessary to correct height differences between the vehicle's left and right sides for the RAS system shall be restricted to what can be reliably achieved with one air suspension height sensor.
The system uses one air suspension height sensor, a steering sensor, generic electronic module (GEM) and other vehicle sensors to measure driver and road inputs. The system changes vehicle height using an air compressor, two air lines and the use of air springs with air spring solenoids.
The air suspension system holds vehicle height when the rear hatch or any door is opened. The system stores rear vehicle height the moment any open door is detected. The system then maintains this height regardless of the addition or removal of a load. The system will return to its commanded height when all doors are closed or the vehicle speed exceeds 16 km/h (10 mph).
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Air Suspension Height Sensor
One air suspension height sensor is mounted on the vehicle. The air suspension height sensor sends a voltage signal to the air suspension control module. The output ranges from approximately 4.75 volts at minimum height (when the vehicle is low or in full jounce), to 0.25 volts at maximum height (when the vehicle is high or in full rebound). The air suspension height sensor has a useable range of 80 mm (3.2 in) compared to total suspension travel of 200-250 mm (8 to 10 in) at the wheel. Therefore, the air suspension height sensor is mounted to the suspension at a point where full rear suspension travel at the wheel is relative to 80 mm (3.2 in) of travel at the air suspension height sensor. The air suspension height sensor is attached between the No. 5 frame crossmember (upper socket) and the panhard rod (lower socket).
When the air suspension height sensor indicates that the rear of the vehicle is lower than trim under normal driving conditions, the air compressor will turn on and pump compressed air to the air springs. When the sensor indicates that the rear of the vehicle is raised above trim under normal driving conditions, this will cause the air to be vented from the air springs to lower the vehicle back to its trim height level
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• Uneven vehicle height

• Circuitry.
• Rear pneumatic fault.
• Air compressor assembly.
• Air suspension control module.

• Go To Pinpoint Test I .

Ride height is directly affected by springs. Old warn out springs will sag. Also if the car weighed down with alot of stuff it will cause the car to ride lower. If the springs are OE I would suggest replacing them with quick struts.

Quick struts are a shock absourber and spring assemby.