Problems with control unit for window lifters

Hello.
a question to the electrical specialists,
have problems with repeatedly empty battery. ==References== 92)
Yesterday, by chance, I found that in the case of a parked vehicle (twisted key), one of the two relays of the window lifter actuation develops a life of its own.
It starts to clock after a few hours in seconds. If you then press the window lifter switch, the disc moves downwards or upwards in this measure.
Question: Is the relay gone, or does it have another reason?
Greetings
Helmut