ignition switch locked up.
 

My car is stuck in a parking lot a few miles from home.

I inserted key and it would not turn. I tried spraying some penetrating fluid in and jiggling but no luck.

So am I in for a major ordeal? I have been reading here for the last hour and searching for solutions. Looks like my best bet is to get car towed home and work in my garage.

Can I access from under dash? What will I need to take apart? I read an article where the instrument cluster will have to be taken out to access. Can anyone give me guidance to get me started? Also, where to buy parts? I understand I can buy a used unit but will have to use the key to match.

I just had my cylinder replaced in my '97 because my old switch blade remote key would not turn the cylinder. Fortunately I also have a new flat key which would turn the cylinder so replacement was easy and inexpensive. Now, with the new cylinder, both keys work well. I think there was just too much wear on the old key and old cylinder. If you have a newer key, try it. It might even be worth getting a new key from the dealer because replacing a cylinder that will not turn, can be expensive as it has to be drilled out. Since yours is a bit older than mine, I am not sure how much of my experience applies.

Jack up one of the front tires and give it a good wiggle. Many times this will free the locking system enough to get the key to work. Plan on replacing the lock in the NEAR future!

Go back to your car, and keep playing with the key. wiggle, jiggle, hopefully you'll giggle (when it turns)

Alot of the time it's caused by the steering wheel locking mechanism. which gets triggered when the key is removed.

You can test this by turning the key to start and turning off, but not removing the key and repeatingly start the vehicle again. keep repeating.

You need a new steering lock and lock cylinder. Yeah you'll probably need to get it towed if you can't get the key to turn. You'll need to get some tools made up to get the lock cylinder out, assuming you do get it to turn. If you get it to turn, drive it home but don't turn the key back to the lock position. Kill the engine some other way like removing the fuel pump relay, then disconnect the battery.
If you have to tow it, I'd recommend pulling the upper steering shaft and working on it on the bench.
I'd recommend getting a matching lock from the dealer. You can go with a non-matching cylinder but is kind of a pain in the butt not having the locks match on the car. Will only really cost you an extra day or two, if that, to get a matching lock.
Good time to replace the ignition switch as well.
Gilly

I have had good luck with this situation by simply ordering a new tumbler (comes with new key) from Mercedes cut to the original code and trying the new key in the old tumbler. Half the time the old tumbler will turn with the new key. REPLACE the tumbler immediately after you get it to turn.

I had a new key from MB made a while back and I only used it once or twice. After getting the car towed home I tried that one and nothing. I plan on replacing the key and tumbler but I don't think that is my problem. I think the problem is the locking pin for the steering column is what is keeping everything from turning.

I can get the cluster out and drop the steering column but where/how do I get to the pin locking the column? I know I have to grind something.

Where?

if you have one of those cheap handheld vibrating sanders you can try that too; i've heard people were also able to use a battery operated toothbrush; the vibrations will sometimes loosen up a sticking wafer

I got the cluster pulled and the lower kick panel out. I have reasonable access to steering lock but I have no idea where to begin.

You haven't said if you got the key to turn, did you get it towed, what's going on?? If you can get the key to turn you have 1/2 the battle won.

If you can't, I usually recommend removing the steering jacket.
The easy way to me is to remove the clamp on the jacket (that the lock inserts in to) then pry apart at the split until the button will slide out. easier to do this on the bench but can be done in the car.

Here's a picture of an ignition lock.
http://farm6.staticflickr.com/5044/5...178ca307_b.jpg
See that hardened plate on the front? That's got to come off. You can't drill through it.
You need to dremel off the black surround to get the plate off.
http://farm6.staticflickr.com/5041/5...66771d81_b.jpg
http://farm6.staticflickr.com/5203/5...ca03c274_b.jpg

Remove your lower kick panel and surround the ignition switch with some towels
http://farm6.staticflickr.com/5128/5...e9d87601_b.jpg

Remove the hardened plate. You will then be allowed to gingerly use a 10mm drill bit and powerful battery drill to drill out the lock cluster. Be carefull and only drill out the lock.

When the lock barrel is out you will be able to use a screw driver to be able to start the car and/or get the remainder of the black collar off.

Go to the dealership and order an original lock or get an aftermarket lock from another source.

I got the car towed to my garage. Tried several methods to get key to turn...nothing works.

So the alternative is to do what Ivanerrol posted, or to remove the upper column. OH or the other thing I described, trying to remove the entire lock in the car. I did that. ONCE. Pain in the butt. Either decide to tear it al apart in the car, or remove the column, leave it all together, but remove it all from the column on the bench. Once you tell yourself that removing the column with the lock in place will be easy, it gets, well, easy. You'll need the lock cylinder and that black cover, the steering lock, and again I'd do the ignition switch, you might need the connector pieces for the wiring where it plugs in to the ignition switch as well, depends on how fancy you want to get and how lucky you are.

So once I grind away the black cover I can access the hardened plate. How does that come off? Where do I drill with the 10mm bit?

Once I get the tumbler out will that disable the locking pin for the steering wheel?

No