Brown earth wires to speedo / rev counter

[silver surfer]

Hi all

Just reinstalling the speedo and rev counter to my 69 280SL after many years. Are the earth wires fastened to the back of the instrument brackets by the knurled nut please?

Many thanks 

[Benz Dr.]

Yes. On both gauges or your instrument lights won't work.

[silver surfer]

Yes. On both gauges or your instrument lights won't work.

Thanks for confirming

[Desertpagoda]

yes, and, according to the DIN standard, EVERY solid brown wire is a ground! if u learn the DIN standard, u will know the function of EVERY wire color! ie: gray/blue....inst lights, red/green...radio power etc.

[66andBlue]

yes, and, according to the DIN standard, EVERY solid brown wire is a ground! if u learn the DIN standard, u will know the function of EVERY wire color! ie: gray/blue....inst lights, red/green...radio power etc.

Hi, I would not mind knowing more about this DIN standard that you mention. I am aware of DIN 47 002 that specifies the color name abbreviation:
DIN 47002:1973-09
Colours and colour-abbreviations for cables and insulated wires
German title
Farben und Farbkurzzeichen für Kabel und isolierte Leitungen.

Which DIN defines the function associated with each color patterns? That would be extremely useful when repairing a harness.

[Desertpagoda]

look here. mine is blue, but...https://www.amazon.com/Automotive-Electric-Electronic-Systems-Bosch-dp-0898835097/dp/0898835097/ref=mt_other?_encoding=UTF8&me=&qid=