Ignition Switch replacement

[GSMITH]

DIY proceedure from my experience on a 1986 560sl.
Part bought from Fastlane. Great service as always.
I have updated it with info for the 107.
Most of this information was found searching this great site and the links provide by other members.
What I did not find was that I needed to remove the knee bolster and to loosen the nut at the bottom
of the steering column. Maybe you do not have to do this for the 124/126 cars but on
the 107 the steering column will not move more than a 1/2".

Tools needed
philps screwdriver for plastic plate behind steering wheel.
flat screwdriver for switch removal.
hex or torx for airbag screws have been reported.
14mm Hex socket with 6" extension for steering wheel.
10mm wrench for clamps.
10mm socket with 6" extension for knee bolster nuts.
13mm wrench or socket for steering column.
Mirror to see the pin in key assembly.

1) Insert key and turn to position 1
2) Remove steering wheel, instrument cluster, knee bolster and cover behind it.
Knee bolster is held in with 2 10mm nuts hidden behind carpet cover.
Access can be from removing 2 plastic covers or 3 half turn plastic screws and
pulling the carpet back till you see the holes.
The instrument cluster does not have to be unpluged.
You just need to get it out of the dash for access to the key assembly.
3) loosen 10mm nut at bottom of steering column while you are down there.
4) Remove wiring connector at the back or the key assembly. May need to move key
back and forth between position 1 and 2 key to get it out.
5) Loosen 10mm bolt to clamp on assembly and move clamp to the right.
6) Push in pin that was hiding under the clamp and pull the assembly out a
little until you can remove the key without the steering lock resetting.
The pin is real hard to see. I used a mirror to find it.
Just because you heard the lock reset does not mean you have failed.
It holds the pin in place. Look to see if the pin is still recessed.
7) Remove 2 13 mm bolts that hold the steering column to the dash
8) Lower steering column while holding the ignition assembly in place until
the lock assembly clears. Might take 2" or more of movement.
If you did not do step 3 the steering column will be hard to rotate and make this
almost impossible to complete.
9) There are 2 more electrical connectors to remove. To remove the one that has a
wire lead to the connector press plastic pins on the wide side.
The other one just pulls off.
10) At back of the assembly there are 3 flat head screws. The switch assembly is not keyed.
If you keep the same orientation the plug will line up when you get it back in the dash.

Reassembly is all of the above in reverse.
Before bolting everything back together tight check the following.
1) Turn key on and check idiot lights. If any are out look at the back of the console to
see if one fell out its hole.
2) Start car and turn on the AC fan. This insures you got the plug back on right.

Hope you find this useful,
Gary

[GSMITH]

I just updated this and saw there were 19 view already.
Since I solved my problems I thought I should post that it has been updated.

Gary

[grindMARC]

I just did this job today. Following your directions (and also those in the service manual), I got caught up trying to remove the wiring harness from the back of the housing (step 3). I had no room at all to get a good trip on the harness. There was enough slack in the wire though to remove it at the very end after releasing the steering lock and pulling out the entire housing.