2001 Ford Exp 220,000 miles Rear not full down (yet) but sinking.

In the last two years, New bags in back new air shocks in front. Working normally until Sunday. Notice the back sitting low. Check both fuses, 109 under hook and the 5 amp inside both good. Pulled the relay behind front rt bumper and jumped the pump and the pump runs. Pump only fills the front, none went to the back. I am not hearing any clicking in from the solenoids? Putting it 4 low does nothing. No susp light.

Things I've tried:
swapped level sensors, and relay (behind bumper)
I have not looked at the sensor on the steering pump but I ran without this sensor for a year and the air susp still ran.

I am stuck. To night I call home and have my wife open the Ford CD and look up the code but thought of here first.

Not much out there on the C1917. I think it could be the Air suspension EVO Steering Module??? It is the only thing I see that could take out all of it.

Also if some one knows a way of just getting air in the back bags, I could get the truck back home in my shop. I am on a trip rith now and headed back in two weeks.

 

Take a look at the level sensor in the front driver's wheel well and make sure the end is connected. It's a ball and socket type of joint attached to the upper control arm and it will pop off when worn.

 

That that was the 1st check. I even hoked up a spare... I had a bad one a while back and it shut down the system.

 

In case you need these. The Air Suspension module (or Air Suspension EVO Steering module) commands changes in vehicle height that are necessary for both the load leveling and vertical height adjustment features. The 4-wheel air suspension (4WAS) system load leveling feature automatically makes adjustments in vehicle height so that the vehicle is always at trim height and constant front-to-rear vehicle attitudes are maintained over the load range of the vehicle. Adjustments in height that are necessary to correct height differences between the vehicle left and right sides for the 4WAS system are restricted to what can be reliably achieved with two height sensors.

The height adjustment feature has three vehicle heights within a two-inch span:

Kneel height — improves the ease of entering and exiting by lowering the vehicle one inch below the trim height in the front and rear when the vehicle ignition is in the OFF or LOCK positions and the vehicle is stationary.

Trim height — normal vehicle ride position; vehicle moves to trim position when the ignition is ON, the transmission is initially shifted to DRIVE or REVERSE mode, all doors are closed or speed of more than 16 km/h (10 mph) is detected.

Off-road height — improves ground clearance by raising the vehicle one inch above trim height in the front and rear when the vehicle is at 4x4 low modes and the vehicle speed is less than 40 km/h (25 mph).

The system uses two height sensors, a steering sensor, GEM and transfer case inputs and other vehicle sensors to measure the driver and road inputs. The system changes vehicle height on the front and rear axle separately using an air compressor, five air solenoids, various air lines, an air spring integrated inside the front shocks and a rear air spring with a solenoid.

The air suspension system holds vehicle height when any door or rear hatch is opened. The system stores front and rear vehicle height the moment any door is detected open. The system then maintains this height regardless of the addition or removal of a load. The system returns to its commanded height when all doors are closed or vehicle speed exceeds 16 km/h (10 mph).

Testing the Pump.
The solid state relay behind the passenger headlight (look up from under the truck to see it) has fins for cooling and four wires. The smaller wires turn on the pump. Jumping the larger wires will test the pump. If the pump does not run this way check for power and ground. If both ground and power are good and the pump doesn't rum its the pump.

Testing the solenoids
The solenoids click loud enough that you can hear them after the truck is shut off and the last door is closed. You should see the truck lower to parked height.
You can ohm these out. As long as there is some resistance they should be good. Mounted on the bags in the back and under the hood in the front.

Height sensors
I have not found a good way to check these. I know these get power and ground from the air suspension module. I believe they give a voltage back to the air suspension module thru pins 9 (rear) and 7 (front). I have see 4 volts is normal. Mounted front left and center in the back.

Rear air fill solenoid
On the frame under the driver. This has to open for air to go to the back. You can ohm this out. As long as there is some resistance it should be good.

Over pressure valve
Mounted above height sensor.


More info:
http://community.cengage.com/Chilton...incoln-4-wheel
Hope this helps others