Eletric problems after big puddle!

[Pichuks]

hello!
So i will get right to the case! About a month ago i got stuck in big puddle,right side carpets all was wet. I got out from the puddle,drived home,no problems,all was working,all was good!
in next morning,i get in car,start it and have "self leveling susp.inact." not working air condicioner,and central locking not locking the doors when i drive above 20 km/h (but with the consule button is working) and rain sensor isn,t working,and when i try to connect to INPA i got error (cant connect to module,any of them wich controls unit who have errors). Ok i understand the water is guilty,i took my seats out,lift the carpet up and dryed all the floor,all the floor mats,all the cables,all the ground block pads,and the fuse box in the passanger side,no watter at all,definetley sure about it!
next day i put it the carpet,put seats in the car,and wollaa problem is gone! no errors,all is working,connect the INPA all modules is found,no errors in them,all is good!
So i drove happy one week and one time had that error again,but switched off ignition,tried again,and its gone,all working!
But now,after one month we have verry hot weather here in Latvia,about +33 and big humidity in air...and damn,the error appeared again,and wont go out,no A/C no door locking and "selflevel susp.inactive" ,and one more thing,while that error is active,the instrument cluster is verry glitchy,and slow,like i swich fog lamps,the simbol appears only after 3 secs,and sometimes i got "dong" after switching ignition out about the errors,sometimes its silent and wont show what errors i had when the ignition was on.
And now i m thiking whats the problem,maybe the big puddle was only coincidence,and i m searching the problem where its not at all!? Maybe LCM or other module is doing all this,maybe instrument cluster?
And final thing,can that be because i didnt screw the screws from ground blocks under carpet and didnt clear them with sand papper or something like that? Can this be the reason of that error appearance?
Please guys help me,because right now i m searching the needle in haystack!
Car is 2000 BMW e39 530Da Touring
Sorry for my English.

[Pichuks]

Anyone?

[Plattus1000]

The power distribution node under the carpet, check it again and look for corrosion. Then look under your spare tire and in that area. If there's any water there, check your rear fuses.

I am in the same position. Good luck.

[schatzy62]

As stated above check for corrosion in the power block under the passenger seat. I had this same issue when a door seal was bad and had a lot of water under the carpet. Cleaned water out, dried the area and about 2 weeks later started having random errors or things not working. When I pulled the carpet up I could see where the corrosion was starting. Removed all wires and cleaned all contacts completely and have had no problems for more than two years now.

But please disconnect both battery terminals before working on this wiring.