Went to start my 300d today, warmed the glowplugs, and upon turning the ignition- before the engine even turned over at all- everything went dead instantly. No power.

New battery, fuses are intact, including Over-voltage protectionRelay.

Would this point to an ignition switch failure??!?
Is there a fuse I am missing?

__________________
OBK #32
1985 300D Turbo (15 gal Greasecar kit installed)
(258,900+mi.) Thanks- Tachometer Fixed. Middle Vents Fixed. Transmission- 1000% better shifting.
Vac leaks- Fixed, Brakes replaced, Steering Box replaced, .... Information Rules.

Sure would be a good first guess to me...
as it happened in the movement phase you were in control of ....

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/diesel-discussion/10414-help-i-need-check-stretch.html

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

My headlights won't even come on. Aren't they separate from the ignition switch or could the ignition switch take that out too?

__________________
OBK #32
1985 300D Turbo (15 gal Greasecar kit installed)
(258,900+mi.) Thanks- Tachometer Fixed. Middle Vents Fixed. Transmission- 1000% better shifting.
Vac leaks- Fixed, Brakes replaced, Steering Box replaced, .... Information Rules.

I'd check the battery cables and battery.

__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

Battery is A-OK. Ground is solid.

Turned the key again just now and got the door alarm to come on,
turned it to glowplugs and it went 100% out again.

Didn't think to check the headlights after the alarm came on.

__________________
OBK #32
1985 300D Turbo (15 gal Greasecar kit installed)
(258,900+mi.) Thanks- Tachometer Fixed. Middle Vents Fixed. Transmission- 1000% better shifting.
Vac leaks- Fixed, Brakes replaced, Steering Box replaced, .... Information Rules.

I agree with Max—headlights are on a separate circuit, should work whether the ignition is on or off. In addition to checking the connections at the battery, check the other ends of those cables. Also see if these is a separate engine-to-body heavy ground cable, somewhere under the car. Safety suggestion: disconnect the positive cable at the battery before playing with the other end at the starter!

__________________

"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

My vote, negative battery cable. It seems that the negative battery cable terminal collects a invisible layer of corrosion that limits the flow of juice. Often times the lights will work but the moment the higher amperage starter engages all power goes out. It always seems to happen out of the blue, on a rainy damp day for some reason. Cleaning the battery terminal and clamp will often restore full power. It is also a free repair, and I always start there first. Good Luck

The exact same thing happens once every year or so on my daily driver (not the Benz).
Same reason: there is a little layer of corrosion building up between the clamp and the battery terminal.
Symptoms are identical: Everything works fine until you turn to start the engine, after that all electric power's gone and stays gone too for a while.

I second the: "clean terminal and battery clamp" advise.

__________________
"The MB W123 is so bulletproof, you can drive them forever. Which is a good thing as it takes that long to get anywhere."
Betsie: 1984 W123 300D (hobby, 280k miles)
Myrla: 2001 Mazda Protege 2.0 ES 5spd (daily driver, 130k miles)
The Turd: 2007 Toyota Camry (wife's car, 118k miles)

Re-checked and cleaned neg cable connection to body. Got glow plugs to light after reconnecting battery but it still goes dead after hitting ignition.

The cable itself is new as of 2 years ago.

I don't know where the positive cable goes from battery, nor where to find grounds that may be under the car.

UPDATE- Just went and turned the key- nothing- then I jiggled the key- somehow got the door alarm to go off. Turned on glowplugs, they lit. Threw it in neutral (1st time I've tried that) and turned the ignition.... Bingo. She started up. Turned her off, then tried again in Park, and she started again.

So, now I'm confused... what did I fix- or is that a sign that it is the ignition switch?!? Doh!

__________________
OBK #32
1985 300D Turbo (15 gal Greasecar kit installed)
(258,900+mi.) Thanks- Tachometer Fixed. Middle Vents Fixed. Transmission- 1000% better shifting.
Vac leaks- Fixed, Brakes replaced, Steering Box replaced, .... Information Rules.

<>Safety suggestion: disconnect the positive cable at the battery before playing with the other end at the starter!<>

NEVER NEVER NEVER disconnect the positive until after the ground/negative has been disconnected from the battery!

__________________

Gone to the dark side

- Jeff

it could also be the ground strap from the transmission bellhousing to the body of the car.

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Sounds like it could be multiple problems. May be the neutral safety switch, cables, grounds, ignition switch and/or shifter bushings....What happens when things don't get maintained....everything fails at one time....

I also see you have a WVO system install.....God only knows how that is wired in, and if that is also causing an electrical issue....

__________________

Yes, that is the engine ground, and on driver's side. It was bad in my 1985 300D, which I found when I had the instrument cluster partly out and saw the speedo cable smoking as I cranked the engine. Sanded both ends and re-installed to fix. One side touches the transmission and aluminum is bad for corroding and giving poor electrical contact.

__________________
1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

How are you testing the battery? How are you testing the ground?

Some FLAPS have a battery load tester that will tell you how many CCA your battery can supply; if new that should match the CCA rating written on the top of the battery.

Testing ground: measure the voltage between the battery terminals, and then between the positive terminal and the engine. If there is a difference that you can measure, you've probably got a bad ground cable or connection somewhere. Try the same measurements while someone attempts to crank the starter. If the voltage measured between the terminals drops below 11 volts, you've probably got a bad battery (shorted cell). If the cranking voltage between positive terminal and engine is significantly different than between the terminals, this again points to either a bad cable or connection (either positive cable or grounding cable or engine/transmission cable to body). The positive cable should run from the battery down to the starter.

__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

I once had a starting problem that turned out to be the starter contacts in the ignition switch. With care, the switch can be removed, disassembled, carefully cleaned, and returned to duty.

Problems with the Neutral Safety Switch are a frequent topic here; wiggling sometimes helps and sometimes the car will start in Neutral but not in Park. In any case, if your car now starts and runs normally, you have disturbed something somewhere that was preventing the car from starting. It will come back! The next time may not be in as convenient a location, time, or weather. I advise going through all of the bits and pieces mentioned in this thread and repairing or replacing all of them. Until you find a smoking gun, everything is suspect.

__________________

"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