What cause Neutral start?
 

My 87 300E wouldn't start this afternoon, it ran fine yesterday. Checked all fuses as that was what happened to my SL a few weeks back. Car wouldn't start in Park, but cranked right up in Neutral. Took it out to have a hair cut and got some gas, now the car starts in Park again, what may be the cause? Should I be concerned?

It could be the switch on the trans. Those are common to fail. Check it out. Good luck !
Brian

Early signs of a failing NSS switch or worn linkage bushing.
Fix it before it leaves you stranded , b/c it will... sooner/later.
...and Murphy says it will most likely fail when you stopped on the side of the road for a quick pit stop at midnight , in the woods on a full moon, a few miles down the road from that prison where those two armed and dangerous death row prisoners just escaped and stole a Benz just like yours...
.. Have no fear though, ..you can just explain the NSS situation to the cops when they surround your car, as it is common for the switching contacts to simply wear out from age/use........:)

Don't do as most .... they change it when it finally goes..

PS... Same goes for Ignition sw. When you have to play around for the trick to turn the key, get it fixed b/c it is one day going to strand you... specially for those foolish enough to have 10 lbs of keys and crap on their key ring.........dumb !

If the NSS swich is bad, can the car still starts at Neutral?

Yes . That is the first sign of a failing NSS.
The P and N contacts in the NSS are the same set , they are just activated in a different position. So, failure in P usually leads to future failure in both P and N .. which means Tow Truck. N only will get you started for a while, but it is a matter of time for complete failure/no start.

The reason I also mention shifter bushing is b/c if the linkage is sloppy from a worn bushing , the NSS lever will not fully engage in P as the shift panel does not allow full movement as the cover acts as a stop for full travel, whereas in N , you have room to giggle it on either side of the N position.
Another reason for NSS failure [ aside from normal wear] is they are susceptical to water and dirt due to their low location on the side of the transmission.
Not an expensive part and an average DIYer can do this job...
The sw. does have elongated mounting holes for adjustment and this sw also incorporates the contacts for the back-up lamp circuit...

nuetral safety switch.
 

These switches (on drivers side of transmission) get a lot of dirt and moisture, Try spraying entire switch with WD 40. These may clean dirty contacts and restore switch capability. good luck, Abe G

Can someone tell me exactly where the switch is located? Do you have a picture of the switch so I know what I should be looking for? Thanks for the help.

Please describe the switch so we know what to look for. Plastic? Wires?