I was wondering if anyone on this site could offer any help on a no crank no start issue. I checked all fuses, the battery is in good condition and I don't want to jump to conclusions on the car needing a starter.

When you cycle the ignition to start position there is no noise from the starter solenoid. I have removed the starter and was going to rewire it pulled away from the flywheel to see if the gear will attempt to engage the starter at all with good supply voltage. Any help would be much appreciated.

 

First make sure the selector is in P or N. Cycle through all the gear positions and try in N.

In front of the battery is a small rectangular box. Use a jumper wire to jump from one of the large posts to the small post with the purple wire. If it cranks, you've got an issue with the neutral safety switch or the ignition switch.
Above the accelerator pedal is a 4-wire plug with a harness that runs down to under the accelerator pedal and to the transmission tunnel. Unplug it, jumper across the two purple wires in the female plug and try to start again. If it starts, you need a NSS.

Good luck!

 

Well still no crank after performing those tests. I'm double checking the charge of the battery on a power supply. I think I will have the starter tested at an Oreilly's or similar. Glow plugs are heating properly per the indicator light. Is there a lockout for any fault in the glow plug system that would kill power to the starter?

 

Had the starter checked. Starter tested good. Going to double check connections and test again.

 

There is no interlock that works with the Glow Plugs to keep your starter from cranking.

Below is a pic of that junction block in front of the Battery that was spoken of before (it is supposed to have a plastic cover over it).
The bunch of wires bolted down to the left are on the same strip of metal and are hooked to the (+) of the Battery.

To the right there is a little plastic divider and one White Wire (this is the one that goes down to your Starter Solenoid) and a Purple one (not relevant to this problem but it goes to your Glow Plug Relay).

If you (wear Gloves incase it gets hot) use a jumper wire from the Left (+) side to the Right (White and Purple wire side) your Starter Solenoid should engage and your Starter should crank your Engine.




In the last paragraph 240D3.OT was telling you how to bypass the Neutral Saftey Switch (make sure your trnsmission is in Park befoe trying to start after you bypass).

 

Hello Everyone. I was very happy to read this thread and couldn't wait to test the NSS on my 1981 300D. I have the same no crank problem,tested starter and ground wires,all OK,still no crank.
The problem is that my 1981 300D doesn't have that small rectangular box in front of the battery,as you guys described. Checked everywhere under the hood to find these 3 screws with the wires connected to them but I cannot find them. Any advise? How to test the NSS? Reverse lights works,starter won't crank in P on N or any gears,only the relay clicks every time. Starter got tested by Autozone and it works,battery is new and fully charged,ground wires cleaned and attached properly.
Please help Thank you

 

Get a test light and probe the wire from the stater terminal on the ignition switch to the starter solenoid, at the solenoid. (Ground the other end of the test light.) The test light should illuminate brightly when you turn the key to "start". If it does, the starter or starter solenoid is bad. Otherwise, work backwards toward the ignition switch until you find out why the power is not getting to the solenoid.

Post a picture of the relay that clicks.

 

I know this is an old thread, but, I don't think this statement is correct. The wires on the center terminal are brown. Brown is ground in Mercedesland. So, if the terminal with the large white wire is connected to the center terminal, as it appears to be, then the large white wire could not be battery plus.

 

Thank you John CC
I am going to work on it this coming weekend,will post picture of the relay.
I was hoping that it is an easier way to test the neutral safety switch ...

 

I'm sure there is, but, without a wiring diagram for your car, it's hard to say how.