86560sel

Well some may know of my car starting problems, well the car starts now and runs fine. (I don't think I posted this problem though on this site, but no matter, lol).

Couple of mysteries here..

I was about to wash the car (1993 400SEL) and I noticed the front overhead interior lights on, then they went off... then I got the hose and looked again and they were on! I stood there and they kept going on and off every 20-40 seconds. When I would lock the doors, they would go off and stay off, but if the doors were unlocked, the interior lights would go on and off. What gives? I imagine that this is what ran my battery down. I am guessing a faulty door interior light switch?

Lastly, the "automatic door closers" had never worked since I have owned the car, but today I closed the trunk and it pulled down on its own! I tried and doors and they work too! What in the world is going on with these? lol.

The MB tech I talked to about the car said they had not worked for years and it was going to be $$$$ to repair, so the owner never bothered with them, now suddenly they work fine.

I thought the interior light deal may be where the auto closer was not closing the door tight, but I closed them tight without the closer doing it and the interior lights still came on and off.

Any help appreciated! The car is a '93 W140.

raymond g-

i'm not familiar with your model, though I have experience with premature
failure of the door/pin switch. you can try taping a coin directly opposite the pin and see if the phantom conditions abate. if so, yes, it's the pin switch.

epasc

Regarding the doors suddenly working, if the power was cut to the pump system (which may also have something to do with your interior lights issue), it has likely reset itself and they will work for awhile but will stop working again, one door at a time, as the brain in the pump finds fault with each door and memorizes the fault. This is the same as the workaround of pulling fuse 9 in the trunk to temporarily restore function to the door closers.

86560sel

Thanks for the replies. Well I did have the battery disconnected for awhile, so maybe it made something start working again. lol. I guess this will be something for the tech to check.

1999 S500

The pneumatic system cost around $3K to replace. (pump, acumulators in the doors, ect...) You will have to pull and reset fuse 9 even after you replace everything in the system on the pneumatic door/trunk/locking system. If a door or the trunk or doorlock is a little slow, the system senses a fault and stops trying to work. It is a feature to protect the pump I was told. There is a work around that you can do that takes the fault logic out and you don’t have to reset the fuse all of the time. I just reset the fuse.

So if you have one of your door/trunk/locking systems stop working, just go into the right side of the trunk and pull that fuse and put it back in. All will be happy again……… for awhile until you have to do it again.

86560sel

Thanks. Well I really don't care much about the auto door closer, I have been closing the doors like on a regular car since I purchased it in September... just thought it was strange that it started working again. I thought it was non-operational for good. lol.

My main concern now is to find out why even with all doors closed, why the front interior lights keep randomly go on and off... they will go off for about 20 seconds, then right back on again for about 30 seconds, back off, then they are right back on again. I don't recall it doing this before and it is surely not good for the battery. lol.

Thanks again.

86560sel

I figured out the problem... I put two and two together and it was where I had not been closing the hood tightly after been working under there. I would just let it rest down, but not latch. After I started closing the hood tightly, the lights quit coming back on. lol.

Thanks again!

oldsinner111

I wasn't aware of a sensor on the hood.I didn't latch mine proper and had no warning.That is a good idea to submit to Mercedes,a hood ajar light,which will reslut in a no start.

86560sel

Yep. I am not sure if that was the issue however, but I noticed that when I would shut the hood completely, the interior light stopped randomly going back on after it went off. lol. If it starts again, I will check that pin switch... you never know about those ghosts. lol.