Rear door actuators --- full of water!?

Both of my rear doors are not responding to central locking (right one was stuck open, left one was stuck closed). I though the actuators might be stuck and need some lubrication so I pulled out the right one . When I disconnected the power cable harness, a stream of water dribbled out. In addition, a significant amount of rust-colored water dripped out of the actuators itself. So I am thinking the actuators got soaked and shorted somewhere. Haven't checked the left one yet but I suspect a similar situation (as a side note, none of the fuses under the rear seat were blown).

I can buy another actuator on ebay for ~$50, but I'm wondering why/how they got so water logged. Don't really want to put in another one if the same thing will happen. Is this a common problem? Should I improve the weather protection somehow? Any advice appreciated.


(car is a 1990 525i)

Rear door actuators --- full of water!?