If you mean the electronic level control sensor, yes there is a way. Firstly, park your car on level ground and measure the highest point of your rear wheel fender well. Then open your trunk and stand in it and have some one turn the key on, if the system is working, it should raise the vehicle up at least an inch to compensate for the added weight. It does this because it will see the angle of the ELC sesnor change, IF the system and sensor is working properly.
Ok, then you can use and ohm meter and check the resistance as you move the height sensing lever, however, you should check for ELC codes. Do you ever hear the little Air Pump running, it should run and then shut off. Sometimes these systems get a leak, and they won't hold any air pressure, so they will never raise. You can check for leaks with with a bottle of spray soap like windex on the air lines and air shocks.
As far as bypassing the height sensor, it will either be in the shorted or open position, which will turn your pump off or run it until it burns up. I would not recommend this course of action.
Moving the height sensor arm with the key on, should operate the pump, or operate the release valves. BE CAREFUL when you are under such a big car. I would strongly recommend that you do it on a hoist. It is VERY RISKY to do it on jack stands.
When you turn the ignition to the on position, the pump will run for about 3-4 seconds then turn off. It takes about 20 seconds after the ignition has been turned on. Can I manually move the sensor to make the pump work?