@funola....Ha! yes it was. Luckily this is a 240d, so I didn't have to deal with the turbo in my way. It was tested at one of those all in one machines at an O'Reilly's - the kind that do alternators and starters. There was no hint of a failed solenoid. It spun immediately on each test. (The motor itself is fine when it cranks).

Unfortunately, I can't remember the power loss happening in the dark - I am sure it has, but I don't remember if the headlights went out or not - I think the console lights went out, but I am not 100% sure.

I will test the continuity at the ground cable attachment point to the + terminal, but I did loosen and tighten the attachment bolt back again and it was totally clean.

Right now it is immobile....I can't get the car to start at all - no click, nothing. and all the cabin lights are strong (I'll check the headlights when I get home). So I can't jiggle the key to see if I can reproduce the power loss.

The local dealership has the switch in stock at a competetive price (and it's less than a mile from my house), so I am going to go ahead and replace the switch.

Can someone remind me what position the key should be in to unplug it? I remember having it in the wrong position on another car and all the wire leads popped out and it was a b@#$h to get them all back in and in the proper ports.

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Current Mercedes
1979 maple yellow 240D 4-speed

Gone and fondly remembered:
1980 orient red 240D 4-speed

Gone and NOT fondly remembered:
1982 Chna Blue 300TD

Other car in the stable:
2013 VW Jetta Sportwagen TDI / 6-speed MT

I hate fixing problems by trial and error. It's more work and can get expensive. Better to do proper diagnostics first and try to isolate the problem. I'd say don't replace the ign switch just yet.

The first thing to do is get an alligator clip of 10 gauge wire to the small terminal of the starter (terminal with the 8 mm nut) and when you have the no start problem, connect it to battery + terminal. If it starts, then the problem is probably in the circuit from that terminal back to the ign switch, which includes the wires and the terminals, the NSS , the ign sw.


Don't bother testing the ground strap or battery cables with a meter. I'm sure ou do not have the proper equipment for that. An ohmmeter won't do.

What you can do is add another ground strap in parallel with the old one and clean or replace the battery cables. Or you can do some voltage drop tests but that requires certain skills for proper interpretation of the results.

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked