Right below the injectors on the driver side they have a wire held by a small nut you should have 5 of them if it's a pre 86 model
Dexron III
The radio code should be on a card in the glove compartment. If you do not have the code you will have to call the dealer to get it.
You can find a wiring diagram for a 1984 Mercedes 300SD ignition switch in the vehicle's service manual, which is often available for purchase online or at automotive bookstores. Additionally, online forums dedicated to classic Mercedes-Benz models, as well as websites like BenzWorld or Pelican Parts, may have user-shared diagrams. Lastly, automotive repair websites such as Haynes or Chilton might offer downloadable diagrams for this specific model.
The fuse diagram for a 1984 Mercedes 380 is located in the service manual. It outlines where each fuse is located and the component it is attached to.
The spark plugs are located right under the exhaust manifolds of both sides of the engine. You should just follow the spark plugs wire from the distributer.
The ignition module is located in the distributor under the rotor, it plugs in.
Which one? That's a good place to start.
made onto the top of the starter/
The same thing happened to my 1984 300SD. I removed the instrument cluster (speedo, tach, fuel guage, etc.). Using a hammer, I tapped firmly on the lock assembly while twisting the key in the tumbler.
The ignition module is located in the distributor under the rotor, it plugs in.
Buy a Hayne's manual for the Mercedes diesel or a Chilton's manual for Mercedes (it has a 123 Mercedes on the cover). It will show you how to change the inline fuel filter and the main fuel filter.
depending on the engine size they will be located in the sides of the heads. look for a rotor cap and 6 or 8 big wires, depending on the engine, then foller them rihgt down to the spark plugs.