It is easy to manually test the SLS system. The lever on the control valve is connected via a linkage to the rear anti-sway bar. The bar rotates as the suspension is compressed or released, moving the level and adding or releasing pressure within the SLS system.

To test, disconnect the linkage from the lever on the control valve and move it by hand. The valve is inside of the passenger side rear wheel. A single 10mm nut is all that need be removed. Start the engine and move the lever up - the car should rise. It takes a minute or two to reach maximum height - a good 2 or 3 inches up. Looks very silly. The valve will make a rather unpleasant noise when maximum pressure is reached in the SLS system, though this causes no harm. To lower the car, move the control lever below horizontal, the car will come down. Don't crush yourself!

I had mine setup so the control level was neutral when the car was unloaded. Adding weight immediately added pressure. This seemed to give decent ride, ride height, and handling.

Note that there is a minimum pressure the valve maintains in the system, even if you leave the control lever below horizontal. The SLS normally supplies some of the suppport for the back of the car, the springs do only a part of the work.

It seems fairly common for the control linkage to slip on the rear sway bar, so it may be out of adjustment.

Good luck,

- JimY