Air Bags fully extended? need help

[Rich8]

My 2000 540iT has been set at a nice lower ride height for the last 3 years.
Suddenly the other night, one blade on the plastic cooling fan broke off, causing ZERO damage as far as I can see.......the dead blade was just resting in the left side by the oil filter housing.
The motor had a terrible vibration until I stopped and took the fan off.
But almost at the same time, the rear air bags went to full inflation pushing the rear up by 3+ inches......full extension
Maybe the fan and the raised rear are co-incidence? I looked everywhere, and cannot find any damaged wires.......anyone have any ideas?

There is a suspension height sensor on the right front wishbone which (I think) sets the height for the headlights, but does it also interact with the rear suspension height? If not, what has an effect of the rear height? The 2 rear suspension sensors seem to be intact, with no visual damage.

[juststeve]

Broken engine bay plastic is common and a sign of poor maintenance. You may want to replace the fan clutch at the same time.

Air pump should have thrown an error code. A stuck air pump relay is the first thing that comes to mind.
There is a PDF manual available on line (e39 air suspension pdf). A search of this forum will yield more information.

[jclausen]

I think the airbags have the sensor on the rear suspension

[geargrinder]

Yep. The SLS uses 2 - one height sensor on each rear corner, not the front one.

[Thundrbucket]

I experienced the same thing on my wagon after I had some work done to the car. Full extension (not fun driving around with!), no errors or signs of mechanical damage. I disconnected the battery, then disconnected the air lines going to the bags to let her drop. Then reattached the air lines, connected battery, started the engine, and hey presto, back to normal ride height. Has been problem free since.