Help troubleshooting W140 No-Crank
 

I have a 95 S320 that is not cranking. I think it had enough juice as all the electrical comes on when I turn the key, but I get no sounds at all out of the starter.

I have read through another thread on here, which was helpful but I would like to clarify a few things. This thread:

http://www.peachparts.com/shopforum/tech-help/209156-mercedes-benz-s320-will-not-start.html

That suggested to pull fuse 16 and check it (I did, it look OK and the cigar lighter works) and the engine does not crank in either park or neutral position (no noise at all) so the next thing I am going to try is the jumper from the battery to the center terminal on X27. My question is how do I find it? The other thread said it was in the passenger footwell on this model, but I did not see anything obvious. I pulled back the carpeting and there was a metal plate at the front, do I need to remove that or it it someplace else?

I found this image looking around the forum:

http://www.classic-roadster.de/cgi-bin/showitemlocation.cgi?TYPE=W140&X=7&Y=7&SORT=ITEM&START=X&ITEM=X27

But I could not find anything that looked like that on the engine side of the firewall so I assume this has to be on the passenger side footwell "BeifahrerfuBraum". What do I have to remove to expose this connector?
Why do electrical problems like this only occur during the winter when it is dang cold in the garage and never on a nice spring day?

Do the "electrical" get dim when you go to the starter position on the key?
Have you looked at the battery terminals to check for tightness and corrosion?
Did you turn on the headlights and are they bright?
Do the lights dim when you try and start the car?
How old is the battery?

I would check these first before you start jumping things.

The battery is fine. I yanked it and took it to my friendly neighborhood auto parts store and they threw it on their load tester to verify the condition.

idiot lights come on?
 

Your problem may be a simple bad starter or bad connection issue. Do you hear a click of any kind when turning the key to start? That may indicate you are getting power to the starter or not. If no power going to the starter... see the comments below.

When you turn the key, do all your idiot lights come on before you try to start? I have a very intermittent starting issue that is much worse with heat. When the issue hits, I turn the key and only the airbag idiot light comes on, none of the others.

This was initially diagnosed as an ignition switch issue, but now I don't think so. I think it is relay or engine harness related. Harness issues are common on 140's is why I bring this up. I can clear the condition by using a remote starter switch with the ignition key set in the on location. My car is a diesel, but you may try the remote starter ( or jump power to the soleniod ) with the key in run position and see if the condition clears.

Chuck

Is there a remote starter somewhere on a Benz? If so, where?

Anyway, after an enjoyable afternoon crawling around and about my car I managed to rule out just about everything (and yes, all the idiots lamps worked). As I went, I gave each connection a good visual inspection and gave some of them a rub with a little brass wire brush I have. Visually, everything looked nice and clean but when I put it all back together . . . yes, it worked. Oxidation is a *****.

Thanks for the friendly advice from all who replied.