Vincentskv99

Hi

Im new in this forum. My s320 1999 acting weird and im out of clue searching for the answer. Suddenly electric seat, power window and mirror stop working when the door closed. But when the door is open everyrhing works. I have checked all fuses and all is good. Also i have changed the un-burned fuses with the new one and still no luck. Yesterday i decided to buy a new battery bcs someone told me it could be a bad battery which will cut unnecessary features. But still didn't do anything. Is there anyone out there with the same problem? Would really appreciate any solutions / suggestions . Thank you

LdeCamp

The 140 has a relay which powers the seats etc. when the door is open. When you close the door, they will stop working until you switch on the ignition system. Probably powered by the same circuit that buzzes you if you open the door with the key still in the ignition switch.

Vincentskv99

Thank you LdeCamp for the reply. So, even with the ignition on it is totally not working. But now, power windows start to operare normally with the door closed. I have checked the convenience relay and it looks fine. I have tried to clean the door pin connector and replace the front pin the the back door pin but still no luck. Once the door pin engaged (door light on) everthing works perfectly. Is the anything to do with the program in the module? Maybe there is any reprogrammed or reset procedure?

For what i understand i can assume that my convenience module, power seat, mirror and steering swith and motor including the wire are in good shape bcs i can perfectly operate when the door open. It seems like when the door closed there is no power / connection to the convenience module.

LdeCamp

I am at a disadvantage because I don't have access to W140 wiring diagrams. I assume you have checked Fuses #30, #35, # 37, #38, # 40 and #41. If you have located the "comfort circuitry" which I assume is, or is within, the convenience module you mention, I suggest disengaging and reseating the connectors to that module. It's possible the lead which tells the module that the ignition key is switched on is making bad contact. I doubt the problem is in the door switches, each of which is only a simple "make to ground" contact when the door is open. Beyond that advice, I'm afraid you might have to ask a dealer or experienced mechanic. Best of luck!

TOYTECK

I HAVE A 94 S420 WITH THE SAME ISSUE. HAVE YOU FOUND A FIX YET? I FOUND A RELAY CLICKING WHEN I PUSH AND RELEASE THE DOOR SWITCH FR THE DOME LIGHTS. ALL FUSES ARE GOOD AND I CHANGED THAT RELAY AND STILL NO GOOD.