Dead key?

[waltklatt]

I wonder if anyone has had this problem before.
I wanted to move my cars around and hopped into the diesel SL with the original key and tumbler assembly.  Twisted the key and waited for the glowplug light to go out and twisted, but the key only twisted 1/2 way.  No click, no starter whirring or anything.  
Tried several times and the key stops short of engaging the starter circuit.
Is this an internal fault of the ignition tumbler, metal part with the key and steering lock assembly or the plastic part in the back?
I will diagnose more tonight by removing the gauges.
Walter Klatt
1967 220SL-diesel
1963 230SL-gas

[Ricardo]

Walt
Your problem is too many cars and not enough room....

I wonder if these tumbler assemblies had the same inherent problems that later benz's had, in that they kind of seize up suddenly and sometimes the key itself becomes jammed....I've read some awful horror stories of keys failing while enroute somewhere and having to drill out the whole tumbler and replace the complete unit....read too that graphite lube will sometimes help with the key assemblies in the 300's (123 chassis)....if you find you need another ignition switch assembly, I have one here that I probably won't need...
Richard

[TheEngineer]

Before you disassemble the dashboard check the starter relay! Look at the wiring diagram in your owner's manual.

[graphic66]

My 66' 230SL did the exact same thing this summer. Nothing worked, I ended up removing the whole lock assembly and replacing it from my 250SL parts car. Upon trying to disassemble the old part I found that it is held together with hardened locking pins that are pressed into the barrel around the lock cylinder. I can't find a way to disassemble it without destroying it. The pins are blind and have a knurled splined outside shape to hold them in. The lock appeares to not be serviceable. I gave up taking it apart but plan on getting into it no matter what.

[merrill]

from what I remember the ignition mechanism has the electrical contacts on the back in a separate module.
That module can be changed out, as long as the key turns the mechanicals are probably good but the module may be faulty.

I will try to find the extra one I have and post a photo.

[waltklatt]

Havent gotten to the garage yet, as it's too cold for my hands to tolerate.  Imagine touching and holding ice cubes all the time.  That's how it feels in the garage.  Now I've paid the price with dry and cracked hands.  So I will wait till my hands heal well and then get to it.  The key turns easily, but the spring loaded action when engaging the starter circuit wont work.  The key stops short of that step.  So my initial diagnosis is the ignition barrel is ok, but the electric switch in the back is out.
Thanks,
Walter Klatt
1967 220SL-diesel
1963 230SL-gas