A few tech questions about the SL R230

Hello, drive even for two weeks a SL500 R230 year 2001 with 84,000km. I have a few little tech problems you can help me. One is the servo closure of the boot lid. This did not work was with Mercedes these wanted to install me a new lock. Then I read here you should pull the fuse F71. This made great, it worked. Yesterday I wanted to close the trunk then the servo closure does not go then tried the boot cover gently slammed the boot cover was too but in the instrument cluster he showed me with red lettering on trunk cover open. I then pulled the fuse then it went again. If the servo closure works after then a noise from the trunk is heard (like when air comes out of a dinghy when a hole is in it) so about 10 seconds long. Can you do something yourself or is here really the lock broken. The second it lights up – if the car is standing one to two days – in the instrument cluster electric consumer switched off. The time until it is extinguished now takes longer and longer. Yesterday had to drive about 10 km until all consumers were switched on again. The seller told me when he bought it he had reinstalled all two batteries. I also don’t know if that’s true. This message also shows it to my wife’s w211 but only in winter when he stands once a week and is then after 2 to 3 kilomets What could be your cause here could give me a tip here. Thank you for your help.