Glad you are all good to go now. One question, does your new switch have spring back from the starting position. I have looked at two now that don't.
One was a MB one was OEM. Kent Bergsma claims they all have spring back, very confused.

__________________
1984 300SD turbo 126
"My true love"

God made me an atheist and who am I to question His wisdom

Yes, my ignition springs back about 10 degrees. The spring isn't really strong but it does pop back a bit when I release my fingers. I guess the car would keep cranking if there wasn't a spring in there.

My tumbler was replaced by the PO. Just checked the paperwork. Maybe that's why mine is still fresh.

I changed out the locking mechanism on my 240d. It jammed up so I pulled the tumbler core and started it with a screwdriver for awhile. I don't recall the spring being in the switch portion. I think it was in the mechanical monstrosity that locks the column, cuts the vacuum etc. Mine was binding on a little cam inside and it jammed up.

I ended up getting the entire mess - tumbler, locking mechanism and switch off a guy who bought the wrong one for his 300sd which happened to fit the 240d. Nearly new for $200.

I recall looking at Kent's info and his tip at the time was changing the tumbler which was not my problem. I used my old tumbler to keep my old keys. Its a common failure point but in my case it was the mechanism in the column being worn and binding.

The big wake up call in his thread is how much current that circuit carries. 8A is a lot to run through all those multiple barrel connectors and switches. The contact resistances must be low or you're going to get big voltage drops.

I guess it is pretty good design because look how long it lasts. My 1999 Accord went through three ignition switches in 106k miles because the contacts in the ignition couldn't carry enough current and burned.

Edit - I will defer to Funola's explanation of the spring being in the switch. It has been too many year since I had those parts torn down on my bench. (2009?)

__________________
79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles

If Kent Bergsma's video says the spring back is in the switch, I'd trust what he says. But you should look at that video again to be sure that is what he said, and that it is not in the lock mechanism.

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Hi guys
Ykobayshi, Did you by chance try the spring back with a screw driver in the slot before you installed the switch ?
Funola, I have great faith in what Kent Bergsma has to say buy I can't find a switch with spring back, not even MB 202-545-01-04. The MB mech says its in the lock itself.
I inquired at MBSource and they comfirmed the spring is in the switch.
S***, I don't know who to believe anymore.
I called Pelican Parts, explained my problem, he did not know for sure but is going to contact their warehouse to test a switch. Stay tuned, should know on Monday.

__________________
1984 300SD turbo 126
"My true love"

God made me an atheist and who am I to question His wisdom

No. I started the car with the tumbler out with a screwdriver and it had spring back. But with this setup both the column lock mechanism and switch were still in place.

I think you're asking me if I can remember if the screwdriver snapped back even when the switch wasn't installed. While I probably tried this on the bench, I just cannot remember. maybe see on Monday.

Kent must know what he's talking about. After going through my Chinese Neutral Safety Switch ordeal I wouldn't install a made in India switch contractor in that circuit. It carries way too much current to put anything marginal in there. And for all I know the circuit isn't fused.

You've saved a ton of money getting it this far on your own. I think it's time to start throwing money at quality parts. My humble opinion of course.

Good luck.

__________________
79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles

Thanks for the feed back. I agree with buying good parts. After returning the made in India switch I ordered one from the MB Dealer. That one has no spring back either. They still have that one for now.
Keep you posted.

__________________
1984 300SD turbo 126
"My true love"

God made me an atheist and who am I to question His wisdom

Took my spare switch off my spare lock assembly and verified the spring back is in the switch. You need a big #3 screwdriver to fit the slot. The spring back is about 1/8 " when turned all the way clockwise. You can check with an ohm meter on the pins for red and VI/WH wire. It should read zero ohms when turned all the way cw and infinity ohms when released. It it stays at zero ohms the switch is ng.

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

THANK YOU Funola for that.

__________________
1984 300SD turbo 126
"My true love"

God made me an atheist and who am I to question His wisdom

Well I finally got it sorted out. The first switch I tried From India was so weak I could not feel any spring loading. The MB switch required a lot of torque on the screw driver to move into the start position.
When I tried it earlier at the dealer I didn't put enough poop into it and could not move into the spring loaded area nor could the MB mechanic who declared "the spring is in the lock mechanism not the switch"
For $68.00 Can I got a real robust switch from MB.
Installing on Wednesday then this will all be over. I hope.
Then I start on the Heating system, oh God.

__________________
1984 300SD turbo 126
"My true love"

God made me an atheist and who am I to question His wisdom

Good luck. It's never ending. While jumping my solenoid I noticed my air cleaner dancing a lot. Broken metal bracket on the intake runner. Gah. At least it gives me something fun to work on.

Slammed the hood and the pad disintegrated.

__________________
79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles

Today was very frustrating. The dam plug behind the switch will not come out even tried gripping with water pump pliers and hitting with a hammer.
I was afraid of separating the plug so I decided to quit when I was ahead.
After 32 years I guess the plug is welded in.
The push button that was hanging through the window is now installed permanently in the dash. The space beside the head light switch has lots of room for a good size switch. I pulled the wires in through the fire wall rubber for the hood pull cable.
I never got to use my spring loaded self locating ratchet to remove the three Phillips screws in the lock. I spent half the night on the thing.
Now my car is just like the new ones with a push button start.

Attached Thumbnails

   

__________________
1984 300SD turbo 126
"My true love"

God made me an atheist and who am I to question His wisdom

Gears, I get it. I have a theory as to what happened. The contact resistance may have been so high that the switch heated up and cooked the connector. Maybe it's smart to stop unless you're ready to replace the cable and connector too. I bet the connector is roasted and requires at least one new socket/pin. I'm not sure they can be individually replaced.

Did you run the button directly to the solenoid? Nice button by the way. I tried but never got mine to work reliably. Either my wiring gauge was too small or my switch didn't have a good enough contact. Where did you get the button?

Also I like the location of your switch...I couldn't find a good place to fit mine in.

I actually still want to install a button permenantly for a backup.

I wouldn't call it quitting. You've just bought yourself some time to come up with a fix at your leisure.

Ps: make sure your wiring is safe. If you are running a hot 12V wire (I suspect you are) make sure it is safely routed so it won't chafe anywhere on the body or else you will have a helluva fireworks show when it does. Vibrating diesels have a knack for rubbing through wiring insulation if forgotten about.

__________________
79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles

it's a lot simpler than that, hopefully. On some Mercedes ignition locks, there is a key way in the electrical switch that prevents that connector from being removed unless the key is turned to the first position, the same position to remove the steel theft deterrent collar. Move the key left / right of position one if the connector still won't come out. It is a pretty narrow window.

Note: The elec switch is held with 3 slotted screws so make sure you have the correct bit. It may be less frustrating to replace them with socket head screws for easier installation.

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Hey Funola. Now you tell me. I did not know about the key position thing.
While I was struggling the key was in the off position.
My Jim dandy self locating driver is Philips so will
change to slot for next time when the switch gives out completely.
It is a drive bit silver braised onto 8mm fanged nut, east to change. Held in the wrench with a bit of good sticky putty.
Any way, At this point I am finished with the start switch.
The button is wired through the vi/wt at the c146 so I still have lock out.

__________________
1984 300SD turbo 126
"My true love"

God made me an atheist and who am I to question His wisdom

oh yeah. That thing!

http://www.peachparts.com/shopforum/attachments/diesel-discussion/124894d1412567944-electrical-connector-rear-ignition-electrical-switch-w123-ignition-switch-t-piece-oct-14.jpg

To discourage hot Wiring? Wow what would I do without this forum.

__________________
79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles