83 300SD Ignition Issue
 

First off, I'm trying to fix this remotely. Just wanted to warn everybody.

So my dad calls me, his 83 300SD (Yes, he went and bought a second benz after I got him the 81 300SD from Tyler) was having the classic ignition lock issue where he can't turn the key to start the car while he was out shopping.

He sprayed PAM in the lock. Yes, PAM. The key turned and he got it home.

After he got back home... he went to town with the lock-ease. And then spent the hour cycling the ignition. Not starting it up, just cycling to the glow plug / ACC , and back. Then he would remove the key, wipe it off and then repeat.

Well now... he can't get it to start. He can turn the key, the radio comes on, the glow plug light... but when he turns it to start, nothing. No clicks, no trying to turn over. nothing.

My guess is that the mix of PAM and lock-ease has gummed up something, but I have no clue what, since I've never messed with ignitions before.

Any ideas?

Is the shifter in P or N?

Sixto
87 300D

If it is in P or N, then try shifting it through the gears, and back into P or N. Then try starting it again. If it works, then it's the neutral safety switch that faulty. If still no go then he's probably shorted something in the ignition. You might try taking the instrument cluster and the kick panel out and have a look at the ignition. Could be the plug on the back or something inside the ignition, which means you'll probably have to take the ignition out and clean it.

If he is in P, and it's still not working, have him jump the two outer terminals in the junction box on the right inner front fender down near the alternator. If it turns over there, the problem is either the NSS or the ignition switch itself. I'm guessing the ignition switch itself given the fact he sprayed a bunch of stuff in there. I'd spray a bunch of electrical contact cleaner in the same way he sprayed the other stuff and see if it helps.
The best way to clean the tumbler is to spray a whole bunch of WD-40 in there repeatedly and let it run out. Then spray some soapy water in to clean it up afterwards.

switch problem
 

It might be the electronics part rite behind the switch. I just changed mine and I was having the same problem a dead switch. The part cost $20 from my local (pnp) and now she starts fine, with the same key try that.

Just experienced the same with my 83 300CD
 

Turned out my problem was more esoteric.

Does his key still have the "spring loaded" feel when he goes to the Start position?

If it does not, the problem is probably the mechanical interface between the switch housing and the electrical part of the ignition switch.

To assist in your troubleshooting, remove the key lock and attempt to turn the switch with a screwdriver. If it works, your problem is in the key lock. If it does not, it requires the following.

To fix, it requires removal of the complete switch housing. A PITA to be sure but if I did it so can you. See many experiences using the "Search" function (including mine). Once out, three screws hold the electrical section to the back of the housing. Inside, the mechanical section has two small "keys" that engage two keyways on the electrical section. In my case,those keys were broken off thus enabling the switch mechanism to turn without moving the electrical switch. The failure was probably caused by repeated and heavy-handed attempts to turn the key as Dear Old Dad has done.

If you need to replace the housing assembly, $200 from the MB dealer not counting the electrical section and the vacuum switch portion. It is shoppable on-line. I paid $145.00 complete with everything but the key lock from **********. Happy Hunting and please keep us posted so as to fill the data base.

Yeah, I called my dad back today and asked him to run the shifter from park through all of the gears and back again to make sure it wasn't the NSS...

Turns out he still had the car in D.

*facepalm*

Once he put it into Park, it started right up.

My apologies for all of this.

oops
 

cheapest BezFix he will ever experience

Man, that's great news!

Ok, Part Two of the saga...

So my dad took the 83 300SD to a detailer (sister had a groupon that she gave him) and they called saying that they had issue getting the car to start. (he was actually at the dentist getting a crown replaces - ouch)

Well by the time he gets there, the car is sitting outside, with it's windows partially down - and the inability for the key to be put all the way into the ignition cylinder. (They claim that they have no clue why the key won't work)

So it's stuck in the parking lot of the detailer. And I know that the only way to remove the ignition tumbler would be to turn the key to 1... which is hard to do when you can't get the key in the whole way.

Any suggestions before the 60% chance of thunderstoms hits would be awesome.