I think the switch itself just screws onto the back of the ignition lock, not need to remove tumbler, but I didn't look while I was in there.

At the very worst you will have to remove the ignition lock, but that's fairly easy -- remove underpanel cover after pulling headlight switch knob and unscrewing the nut underneath, remove cover and pull cover around ignition switch to reveal top screws. Pull carpet to get the plastic nuts off the cover, then remove. A bit tight, don't break it. Ignition lock is held on by a couple bolts, just remove, then turn key (I think) to get it out. Switch is, I believe, held on by a couple screws on the back side.

Best course of action is to get a proper manual, you won't break thinkgs that way.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!