I have a 85 300d w123. Lately the blower motor will not work unless I turn the ignition switch backwards a touch. I hear a click and the blower motor works. Now I have to toggle the switch 2-3 times to get my glow plug light to come on. I noticed this problem when I was having trouble getting it to start. Is this indicative of a bad ignition switch?

85 300d w123 190k miles

Probably. Might be able to take it apart and clean some corroded contacts, else replace, about $30 on-line, more from the dealer.

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

Had to replace my sons ignition switch electrical connection unit. It's on the back of the tumbler assembly. You can unscrew the electrical unit from the back of the assembly from under the dash. But if the small shaft unit that goes into the switch is deteriorating as my sons was then the whole assembly must be replaced. The service manual covers the R+R of the whole assembly.
Try to remove the rear electrical switch. If it does not come off then you will have to replace the whole unit.

Dave

__________________
1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car

If you've never done it before I would highly recommed the diesel giant article. I spent the better part of two days trying to pry the ignition from the steering column because I could not locate the locking pin. This article is very good with lots of pictures.

http://www.dieselgiant.com/repairignitionlock.htm