Hi All, I am a newbe I bought a 87 300d in april of 2007,your comments have helped me out alot,I am also new to diesels so I have been learning alot as I go, here is the problem,(s)
1) Glow plug light has never worked since I have owned the car I beleive the light might be burned out, as I have no problem starting car,It was down to 22 the other night.
2) when I turn the key and start the car ,the only way I can get the air to blow out of the defrost and left and right vents is to turn the key a fraction ,then it will work but only out of those vents, in the summer the same thing so it will blow heat if I do not turn key a fraction to keep heat from coming out.
3) The Big problem, I drove car yesterday same as always, when I went to leave a hour later, I turned the key as always for the glow plug warm up and nothing happened, radio worked, dome light, head lights, power windows,I thought I could have left some thing on,but I did not, I put on Jumper cables , charged battery, (72 Month just bought in july) still nothing, not even a slight crank. this has never happened,

I was thinking that it could be a ignition switch, since the way I need to turn key to get fans to work, or is there some thing else to look for, if it is are they hard to put in ?

I have looked for threads to this problem and have not found one

PLEASE HELP, ANY HELP
Thank you Jeff

A couple of other things to check:

Try wiggling the transmission selector in and out and back to park or put it in neutral. It may be a Neutral Safety Switch on the transmission.

Since you now have a charged battery, try using one of the jumper cables from the battery (-) to the block. If it starts, then it may be a loose chassis-engine ground strap. This is something I came across.

A remote possibility, a broken terminal lug at the starter is something else I've seen. However, you have mentioned previous problems with the ignition switch and likely could be the source of the problem. New ones, keyed to original, are available at the dealer with registration for proof of ownership.

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Sam

84 300SD 350K+ miles ( Blue Belle )

Have someone turn the key while you stick your head under the hood. Does the starter solenoid make a "click" sound? If not, your solenoid may be bad, or perhaps the wires are loose. Be sure to disconnect the battery before messing with those wires though. If the solenoid does "click", then the starter may be bad. Either way, you will probably end up replacing both.

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1987 Mercedes 300D ~200K (Greasecar & Biodiesel)
1993 Ford F-250 7.3 IDI diesel 165K (Biodiesel)
1996 Thomas/International Bus with DT466 engine

Don't run and replace the starter motor until you try turning it over using the three-trminal contacts strip provided for that purpose. Its somewhere near the Battery. You jumper the end contact to the center contact, I can't recall the proper orieintation but it won't hurt anything if you connect the wrong ones. This should actuate the solenoid and the starter will crank the engine but without the key in the center position the fuel supply will be shut off so the engine won't start.
From the description it sure sounds to me like the ignition switch may be bad.

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

I am having car towed to my house on thursday, just trying to take in as much info. as possible,is there a fuse or relay that could be bad? I looked at fuses in fuse box ,they all looked good, but I know there are some strip fuses on this car also,if it is the ignition switch ,do I need to replace the tumble also,as I see that there are different parts for sale?
Thank you for your input, Jeff

Nope, no fuses on the starter circuit.
Get a short length of insulated wire (heck I have use two car keys held together in a pinch!) strap it across the two terminals I descibed and see if it doesn't turn over. If so then your starter is OK, that is the big thing that needs to be determined, then you can rest easy that the failure is a small external electrical part, it could then be the neutral sensing switch or the starter switch, both are much cheaper (and easier ) than replacing the starter.

You may as well do the above test before having it towed because if the lock in the dash is bad you will probably wind up towing it to a shop. Or have a locksmith come out to replace it (its possible to DIY if you are very good with your hands).
If the ign switch is bad you can just lay across the seat and remove it after taking off the lower knee panel but its not a job I'd want to do in inclement weather.
If your key works ok without having to jiggle it in the cylinder to turn it then the tumblers are ok and you won't have to order a new cylinder. BTW the OE code cylinder is a dealer only item. If you order from the online catalogs you will wind up having to use a different key for the ign than for the doors.

I'm still betting its the ign switch!

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

As diehard says, except on your car the terminal strip is just forward of the brake booster.

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Gone to the dark side

- Jeff

could you tell me where the brake booster is on this car,
front,back ,left, right, I do not have to jiggle the key to get key to move,I just have to turn a fraction to either get the blower to come on or not

Thanks Jeff

Brake Booster, attached to the brake master cylinder, just above the driver's feet.

One problem might be getting the glow-plug circuit to work, it will be difficult to start the car in anything other than warm temperatures without.

The terminal strip discussed is behind the LF strut tower, attached to the top/inside of the outer firewall. It is black with three screws/terminals.

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Gone to the dark side

- Jeff

Thanks for location, I will look tomorrow, and it was said that I will not do damage if I cross the wrong terminal,is that true?
Even if it does not start but tries to what would I look for next?
and would a no# 12 house wire work for what I could use to make a jumper?

Thanks for all the info Jeff

When you turn the key you get nothing?

Smack the starter with something, see if that does it.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200