ADS not operating on 1998 S600

[bakselrud]

The ADS module (under the rear seat) does not control any of the suspension solenoid valves. The ride is hard. I have done the following to diagnose the problem:
1. No ADS MIL is present
2. NO OBD or MB scanner codes present (I have MB diagnostic tools)
3. I followed point by point comprehensive ADS electrical test from MB STAR manual and every connection, voltage and resistance value checked within its operating limits.
4. The ADS engage/disengage switch on the dash board along with its LED indicator light is operating and measures correctly according to the STAR manual.
5. I tested acceleration sensors on the front and the rear struts with oscilloscope and verified that they are operational and respond to the vehicle movement.
6. I unplugged ADS module and hard-wired all suspension solenoid valves open (2 per wheel). The suspension switched to soft mode as a result.
7. I ordered another ADS module (from potomac) with the same part number and software revision and used it instead of mine. That made no difference, the new module is ether broken or not operating for unknown reason.
8. I studied the schematic of the ADS system external connections and do not see anything else that can be at fault. The ADS system is pretty much self contained requiring only:
- Steering angle sensor (that has no problems and is initialized just fine)
- Accelerometer sensors (all checked fine)
- On/Off ADS switch (Checked fine)
- Power supply (checked fine)
- Solenoid valves (all checked fine)
- VSS
9. When the key is first turned on to start the vehicle and right after the engine start, I can hear (and test with a multimeter) that the ADS is clicking the solenoid valves in the rapid succession. However after that, ADS module refuses to energize the solenoids.


DOES ANYBODY HAVE ANY OTHER IDEAS?????