I have an 83 300D I just acquired a couple weeks ago. Just finished removing the dash cluster so I could fix the broken odometer. Put everything back together carefully and even ran a separate ground wire from the cluster to the frame. Not sure if the cluster work is related.. but now when I go to start the car I turn the key the 2nd position where the seat belt and Glow plug lights come on. Once the glow plug light goes off I try to turn the key further to engage the starter and it will not go. It's sometimes I will hear 1 click, but it's like the key will not advance and farther? Now I'm not hearing any click when I try to start.

I've done the following..
- Moved shifter around and tried starting in Park and Neutral (same result)
- Manually jumped the Starter by using wire. Car started right up with no issues.
- Removed battery wires when working on the cluster. Cleaned and checked terminals.
- Checked Glow plug relay and fuse is good..

Originally I thought this may be some grounding issues, but the car was starting perfectly
before I worked on the cluster. Battery is obviously good...

Not sure if this is related to glow plugs possibly? Or is it something with the ignition key
tumbler ?

I'm guessing this is something stupid easy I'm overlooking.. but still have a lot to learn.

Cheers!

Sounds like something's not making contact because it cranks when you manually turn on the starter.

page 11 of this pdf has the wiring diagram for your starter circuit:

https://www.startekinfo.com/StarTek/outside/12265/disc_2/program/ETM/83_300.pdf

Doing this "Moved shifter around and tried starting in Park and Neutral (same result)" dose not rule out the Neutral Safety Switch being no good.

There is an electrical connector where you can bypass the neutral safety switch See the pictures in post 2
http://www.peachparts.com/shopforum/diesel-discussion/401931-w123-diesel-auto-starter-lockout-backup-switch.html

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84 300D, 82 Volvo 244Gl Diesel

Thanks for the suggestions.. I was able to bypass the NSS with a wire as shown in your link below. Unfortunately, that did not help the issue. I still can not move/turn the key any farther to engage the starter. It's still locked at that spot. Is it possible I have a bad tumbler or Key assembly? The key is the original one from 1983 and is quite worn.

Any additional ideas?

I believe you may have a bad ignition lock which is preventing you from turning the key to the actual start position. I was presently surprised to find the genuine mercedes ignition lock is available on this forum. As far as I'm aware, only Meyle now makes the key assembly. Here's the mercedes igntion lock link:


https://www.pelicanparts.com/catalog/SuperCat/3305/MBZ_3305_ELIGNT_pg2.htm


I don't know where to purchase the meyle key assembly for your car but I'll keep looking and let you know if I find it.


If you do purchase the genuine mercedes ignition lock from pelican parts, you might want to take your car (have it towed if necessary) to an auto electric shop that specializes in german cars. Check out their reviews on google and yelp before calling for an appointment. If they know what they are doing they will be able to get you going.

I must have missed the key not turning. As said the Lock Tumblers have issues or like happened to me the inside of the steering Colum lock between the Lock Tumbler and the Ignition Switch broke.

I thought I had a key tumbler issue.

If you get the Key Tumbler out also pull the Steering Colum Lock and see what it is OK inside. Also the Steering Colum Lock replacements are presently hard to find.

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84 300D, 82 Volvo 244Gl Diesel

My steering Colum Lock thread
http://www.peachparts.com/shopforum/diesel-discussion/333785-steering-colum-lock-ignition-lock-housing-causes-ignition-switch-failure.html

People have occasionally been able to free up their Lock Tumblers and get the key out. I fooled with mine a bit for several days and when it turned I turned it to the position to pull out the Lock Tumbler. Also on mine in order to pull out the ignition switch it needs to be in the position you remove the lock tumbler from.
On the earlier W123 Models that feature is not present.

Repair Links
Fast navigation http://www.peachparts.com/shopforum/diy-links-parts-category/146034-fast-navigation-do-yourself-links.html

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84 300D, 82 Volvo 244Gl Diesel

I almost forgot, I've been using Super Lube Lock Lubricant for quite awhile now and it works miracles. It certainly won't hurt to spray this into the key hole and give the key a try. I spray my door locks, trunk locks and ignition locks with this stuff regularly and bottom line is IT WORKS!


https://www.amazon.com/Super-Lube-31110-Aerosols-Multi-Purpose/dp/B0016GTSBY/ref=sr_1_2?dchild=1&keywords=super+lube+lock&qid=1599657463&sr=8-2

Hi Diesel911/Merc,

Thankfully my key wasn't stuck on the Tumbler, actually it's so loose that the key slides out regardless of what position it is in. I was able to use a metal pin rod to remove the tumbler
and have ordered a replacement one.

Is it ok to use aftermarket tumblers like the ones sold here on Pelican Parts? $20 is much easier than having to spend $180 for a Mercedes one.

I saw the posts about Diesel911's horrible steering/starter issues.. I'm really hoping I don't have to go through all that. Is there anything visual I can see on my tumbler or the inside where it goes
to tell if something was broke?

I'm hoping to try a new key/tumbler with some Super Lube may fix it.


thanks again!

What ever tumbler you get don't hang a large wad of keys off of the Ignition Key.

I have had a Meyle Lock Tumbler in mine for I think it is at least 2 years. But, I fixed my Steering Colum Lock so that it does not lock. That removes a lot of spring tension off of the Tumbler when you turn it. Because of that it is not a good test of the Meyle Tumbler.

When you try to start have you tried disconnecting the vacuum tubing at the vacuum shut off?
The below dose not happen often:

Stuck Steering Colum Vacuum shutoff valve keeps car from starting post #8
http://www.peachparts.com/shopforum/diesel-discussion/333097-thermostat.html

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84 300D, 82 Volvo 244Gl Diesel

Hi Diesel911,
Still waiting for my new tumbler to arrive in the mail, but in the meantime now that I have the old one removed..should I be able to turn the ignition manually with a large flat head screwdriver? As long as I press in that small metal button inside at the bottom (steering lock release?) At this point I'm still bafftled why I can't turn my key past to the point to engage the starter.

All the articles/videos I watch with key/tumbler issues always seem about the key not even turning initially (to the Accessory position). I have yet to come across any reference to the issue I'm having where the key will turn fine to the Accessory position and beyond... but won't turn the final move to engage starter.

Thanks again...

p.s... I didn't check anything on the two vacuum lines to the ignition since I never touched those or removed any of the ignition assembly besides the tumbler.

Well.... I answered my own question. Not sure why I didn't think of this earlier.....

I took a wide flat head screw driver and inserted inside the ignition assembly (with the tumbler removed) and was able to start the car just by turning the ignition assembly. Just had to press down on that small triangle piece inside the housing and it slides over to the right as you turn... but viola! It started
no issues.

So no I know it's definitely a Tumbler problem and hopefully the new one will fix it.

Thanks!

Excellent. Go for it. Take some pics of the process for those of us who have never done it.

I guess I spoke too soon... Got the new tumbler in the mail and installed it. But I'm getting the exact same problem.. The key won't turn past the 2nd position to Engage the starter. So it now appears that something is bad on Ignition assembly and it will have to be removed and repaired/replaced. The only issue is you can't buy these new anymore from what I cant tell, only used ones. Does anyone know otherwise or have suggestions?

thanks,

Get a new key VIN coded from dealer and/or replace NSS?

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78 W116 300SD 'Desert Rose' new as of 01/26/2014
79 W116 300SD 'Stormcloud' RIP 04/11/2022