Starts in run position 1985 300D

[my123ca]

85 300D - Car would start in run position and starter would continue running even with the engine running. Broken steering lock, tumbler, ignition switch or all of the above? Does part# 1264620730 include everything including key and ignition switch?

[optimusprime]

my123 sorry to say it looks like lock replacment is on the books for you .Had this with one of my cars .It was an Humber Snipe .I was the culprit .The key was stiff going in ,so i put a little grease on the key, i pushed it in a few times .Started it up would not stop after i turned the key off. The contacts in yours have worn out in the switch .. Look in the tech info top of this page .All repairs under the sun in there check it out .

[Diesel911]

Originally Posted by my123ca

85 300D - Car would start in run position and starter would continue running even with the engine running. Broken steering lock, tumbler, ignition switch or all of the above? Does part# 1264620730 include everything including key and ignition switch?

I did not spell check the below.

If you have an automatic transmission your neutral safety switch is supposed to prevent you from starting in anything but neutral or park. However, if your Shifter Bushings are worn you sometimes can start in other gears or if the neutral safety swith has been bypassed or is not lined up correctly (there is a hole in the transmission housing and one that is in the neutral safety switch to allow you to insert a properly sized drill bit so that you can line up the neutral safety switch properly).

If some sort of wear inside of the neutral safety switch can allow you to start in other gears I have not read that in any of the threads or posts I have read.


The Key and Tumbler are seperate and do not come with the Steering Colum Lock Assembly.

The part you are speaking of comes with the Ignition Switch (which is actually at the bottom of the Steering Colum Lock), a Vacuum Shutoff Switch (the one that screws onto the Steering Colum Lock not the one on the Fuel Injection Pump) and the Steering Colum Lock (incorperated into the aluminum housing) itself.

I got mine from an online Mercedes Dealer that sold the parts on the internet but it is no longer around. Anyway, the steering colum lock assembly was made in France by Neiman.

I could have saves a little money by getting a Valeo Steering Colum Lock Asembly because Neiman/Valeo are different parts of the same company.

Beware of only shopping by the price because Myele also sells the Steering Colum lock without the new Vacuum Switch or Ignition Switch as well as the complete assembly.

Random info.
Please note that these days calling the Key and Lock Tumbler the Ignition Switch is jargon. On my 1953 Chevy Pickup Truck the Key the Lock Tumbler and the Ignition Switch are all one assembly. So that could be rightfully called the Ignition Switch.

I am not sure after what point in time but sometime when they started incoperating Steering Colum Locks into Cars the Ignition Switch got relocated from the Key and the Lock Tumbler. On My 1986 and 1992 Chevies the Ignition Switch is on the bottom top of the Steering Colum about 2+ feet from the Steering Colum Lock and the Lock Tumbler.

[Diesel911]

My steering Colum Lock thread
Steering Colum Lock (Ignition Lock Housing) causes Ignition Switch Failure

[my123ca]

The starter will engage with the key in the run position and the starter would still spin even when the engine is running. I looked in the DIY section but did not find anything regarding the removal of the steering lock. Im trying to narrow down the problem whether it is the steering lock or the the ignition switch. How hard is it to remove the steering lock? Does it involve removing the tumbler?

[Diesel911]

Originally Posted by my123ca

The starter will engage with the key in the run position and the starter would still spin even when the engine is running. I looked in the DIY section but did not find anything regarding the removal of the steering lock. Im trying to narrow down the problem whether it is the steering lock or the the ignition switch. How hard is it to remove the steering lock? Does it involve removing the tumbler?

One of the Wires coming off of the Starter small terminal goes up to a Wire Junction Block. On mine that wire is white.
When your Starter is cranking that white Wire gets voltage.

When the Key is in the run position you should get no voltage from the white Wire. If you do you have an issue with the Ignition Switch or the Steering Colum Lock.

4 things that can cause the Starter to stay engaged are the internal mechanism and the Starter Solenoid full of thick gunky Oil and or dirt causing them to stick forward because the gunk will not allow the spring to allow the parts to pull away.

Another is if the Flywheel has burrs on the Ring Gear teeth they can sort of hook on to the Starter Pinion Gear and keep it from pulling out.

Problems with the over running clutch (often called the bendix but it is not a bendix) and the Pinion Gear.

I don't know what causes this and it rarely happens but when the Starter Solenoid activates a plate moves towards the read and makes 2 electrical contacts. One with the Battery and the other with the starter.
Sometimes the contacts sort of weld themselves to the plate and won't let it go.

[my123ca]

Originally Posted by Diesel911

One of the Wires coming off of the Starter small terminal goes up to a Wire Junction Block. On mine that wire is white.
When your Starter is cranking that white Wire gets voltage.

When the Key is in the run position you should get no voltage from the white Wire. If you do you have an issue with the Ignition Switch or the Steering Colum Lock.

Im getting power from the white wire in the run position. Removed the small wire to the starter for now so i can move the car. Could put a push button switch using the white and small wire for now until parts arrive.

[vstech]

I had a similar problem when my glow plug controller quit... Try unplugging the small wire set from the glow controller...

[BillGrissom]

Sounds like the switch is bad, since it should not crank in the "run" position. In U.S. cars, I term the positions "accessory", "run", and "crank". M-B terms them "position 1", "position 2", ... and there are tic marks on the key side.

I removed everything in my 1984 300D to get at something that was jamming the rotation (broken spring holder in "detent" behind steel plate of lock assembly). Anyway, no need for that. The switch installs on the rear w/ 3 screws (slotted). Pull the connector off and you will see them. The problem is getting a short screwdriver on them while you can't see. When you install the new switch, rotate the key until the fingers align. A new switch was ~$20 (not M-B brand).

But maybe don't listen to me. The switch in both my 300D's has started acting funny w/ the glow plugs. I don't get the g.p. light the first time, but if I try again I do. In one car, the g.p. are powered even though the lamp doesn't show, but not in the other. Also, I recall when I got the 1985, if you came off "glow" you had to go all the way left before it would let you rotate back to glow (feature?). Doesn't do that anymore, but I like it. Can't recall if I changed switches in both cars. When I did, it didn't fix the issue I was having.

[Diesel911]

Originally Posted by my123ca

Im getting power from the white wire in the run position. Removed the small wire to the starter for now so i can move the car. Could put a push button switch using the white and small wire for now until parts arrive.

If you remove the other Wire from the Small Terminal on the Starter Solenoid you leave the White Wire attached; you can wire a Switch to either of the 2 Rear Terminals on the Junction Block as they have + Voltage.