i was wondering if there was a diagram for each individual wire going from the glow plug relay to the dash(in that smaller connector). I am trying to figure out if a wire is bad and wanted to know where each goes.

Also, is there a guide/documentation on how to run a wire from the engine bay to the instrument cluster?


Thanks!

Car: 82' 240d

There are paper copies of the service manual, with wiring diagram, available on the aftermarket (used). That will have what you need. I think they are in the Chassis manual, big thick heavy book. Might even be two volumes?

When I ran wires for a tachometer and an external temperature display from the engine bay to the dash in my 123 wagon, I had to play contortionist under the dash. In general, there are rubber plugs in the firewall that the wires go through, or they go to the fuse box area and then under the dash. One idea is to use an old wire that you know is bad to pull a string or wire through, and then use that string/wire to pull you new wire(s) through.

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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

yea one of the wires i am installing is going to use a fuse in the fuse box. But i guess i am trying to figure out a way to nicely run a wire from the engine bay to the fuse box, and fuse box to the interior.

obviously getting to the fusebox is easy ... but that last leg.. fusebox to dash seems... weird?

This is from another post where someone was asking where they could install a manual Switch for the Glow Plugs.


1) rd/bk (Black) ignition switch (Voltage goes thorugh this to turn on the Glow Plug Relay, if you cut the Wire and wired a push button Switch to it and your GP realy is still good you could use the button Switch to turn the Glow Plugs on and retain the feature that tuns the Glow Plugs on while the Engine is cranking bay way of the Purple Wire on a W123. I also believe the Glow Plug Light would still work if you do this.)

2) vi (Violet/Purple) On turbo models goes to a Wire Terminal/Junction block and mates with a White Wire coming up from the Starter Solenoid. When you Crank the Starter + Voltages goes through the White Wire to the Violet one and turns the Glow Plug Relay On. (You could disconnect this wire at the Terminal Block or the small Terminal at the Starter Solenoid and wire it to a push button Switch.)

3) blu/wt (Blue with white strip)glow indicator Light

4) br (Brown)ground

The above would be for my 84 300D. If the Wire Colors are not the same the Numbers on the Connector like #1 going to the ignition would be the same.

On he non-turbo W123s the #2 (Violet/Purple) would go to the Starter Small Terminal.

I have noticed in that last 2 Months quite a few people asking questions that would be easier answered if they had a real Mercedes Service Manual.
When I first got My Car I was desperate for information and got the Mercedes Service Manual on CD, The Haynes Manual and later a used set of printed real Mercedes Service Manuals.
They quickly pay for themselves in time, convenience and money.

If you can you can access the free Manual on the Mercedes EPC but I don't need that so I don't use it. Perhaps some Member can be of help on how to access it or can supply the diagram from it.

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84 300D, 82 Volvo 244Gl Diesel