stevenjag

Hi everyone i am new to the forum, just bought a 2003 mint s class 320 petrol lwb, and am sold on how great mercedes really are.
Had an issue display defective comes on screen and visit workshop/lighnting flash sign...
Head lights flash, relays click all electrics go crazy and parking light and srs light intermittantly come on...
We plugged it in snapon code reader (with all mercedes software),cleared the myriad of codes listed due to disconnecting battery
Defective display came back on and large fan at front of car started up quite loud then stopped...
only code showing was air con pressure too high
the air con led had been on due to no gas (not too much in system)
checked gas was low as i knew but no leaks-checked codes again after clearing pressure sensor came up...aac
did manual code check on air con inside car came up with aac multi function sensor code 1269 i think it was?
the mechanic says regas change sensor and reset codes again should fix it as he thinks the circuit for aac etc is tripping the weird electric crazyness inside car??my other mechanic mate said aac doesnt effect anything on electrics??
seems to make sense if on these forums people seem to link coolant sensor to dash malfunction surely any sensor thats broke could do same?...any ideas?
my guy says car is reading high pressure aac so car is thinking its too hot...hence fan coming on...correct or rubbish..i will also change coolant sensor, and washer fluid sensor...do these things run on same circuit...no other malfunctions or running issues air susp works fine, just loose all electrics like door locking and windows when defective display shows.
any help mucho appreciated

ibeforreal

A bad or weak battery will also cause the electronics to go wacko. The car may start and run ok but then a bunch of gremlins show up if the battery is not up to par.

stevenjag

Yes we thought that, but tested the voltage output while car was off and while running and using electrics showed either 14/13.48 so its not the battery by look of it......

stevenjag

is it plausible that the air con pressure sensor/system could be the culprit?

tusabes

I saw a car where headlights Flashed and relays clicked and display defective it was the bad drivers door control module

stevenjag

HI thanks for replies, is that door module inside the door itself?car isnt locking now either...with fob,ill replace the other 3 sensors fri and have air con gassed...i will plug in STAR READER tomorrow i think see if it highlights any other specifics...seen lot threads relating to this issue with dash defective but no cures...has anyone had it fixed definitively?

tusabes

Again I saw a car with the exact same problem and yes a door control module fixed it
That doesn't mean it's the same problem in your car since everything is interconnected on these cars

But the DCM is a very common failure item . It's in the door behind the power seat switches (it's actually the whole drivers seat switch assembly ) . Get one on eBay with a return option or warranty . If it's not the problem , then you can return or relist the item for sale to someone else . They sell easily as everyone needs it . Get the one with the same seat heater buttons as yours (3 lights or 5 lights depending if you have heated and cooled seat or just heated seats)

stevenjag

Hi everyone, used the star reader, found wiring issue in passenger door, returned to garage 1 hours labour, rear door panel off looseterminal cleaned fixed and no more issues since! Fixed hopes this helps anyone with similar problem!!
Soft close doors stopped working and locking, changed yellow 20A fuse under seat at rear of car, again fixed all for £50.50 great result!!