A Simple Remedy for a 12-Volt Supply and Starter Switch Port in the Engine Bay

By Albrecht Stachel

It has always been annoying to work with the engine without the benefit of 12-Volts readily available under the hood.  The simple task of ignition timing and rotating the engine with the starter is easily improved with the installation of an electrical 12Volt port on the bulkhead.  I determined to remedy that situation in W198 cars being worked on here.  The fixture is completely removable as necessary to return back to O.E.

























I made a small two wire harness attached to the starter solenoid and ending up on the bulkhead horizontal tray.


















The main 12V lead consists of a 16-gauge wire (red) terminating on a standard DIN two post junction block found on many Mercedes cars of the fifties and sixties. The second wire is a 18-gauge violet (standard DIN color for solenoid engagement from the starter switch) wire from the solenoid starter engagement position to the other contact on the new junction block.



























It is now possible to engage the starter by bridging the two wire connections, preferably with mechanics wire lead starter switch. No need to reach into the cabin and engaging the starter from there anymore. It is critically imperative to provide the 12V hot shoe with an insulating cover. An incidental or accidental contact with the 12V hot is highly undesirable.

The metal bracket is a simple bending of a suitable piece of metal, aluminum or steel, to mount the connector block and a hole to fasten the metal bracket to an existing fastener on the bulkhead shelf.

It makes ignition timing particularly convenient to connect the timing gun 12V lead, now readily available.