{HELP} 1973 230 wiring !

[-Merc-]

Hi all i just got my first car 3 weeks ago and shes a 1973 230 compact, well im 15 and not a wiz with 30 year old german wiring. i have taken out the factory radio system and was in the process of replacing it with an alpine cd player i got from my uncle.

NOW we come to the problem as i cannot seem to find the earth wire to hook up the system. i need urgent help as ive already electrocuted myself at least 10 times with the faliure to disconnect the battery (my stupidity).

PLEASE HELP

 

[Ted]

It's the brown wire.
No tracers, just solid brown.

 

[-Merc-]

Why thank you Ted

 

[grober]

On older radio systems and cars the radio was often mounted by its front knob spindle nuts to a metal cutout plate that formed part of the dashboard. This was often employed as the system earth by default altho there was usually a earth connection point somewhere to the rear of the radio usually in the form of a large threaded stud which could also be used as an additional mounting point/bracket. Because the dashboard was usually a metal pressing welded to the rest of the body shell this arrangement was fine. Modern vehicles with dashboards made multiple sections consisting of plastic mouldings require require discrete earth supply wires often leading back to a common point/points on the metal bulkhead behind the dash. For this reason you probably need to run a new earth wire to your ICE system. you can attach this to any good body earth using an existing earth point or make your own using a suitable nut/bolt/lockwasher or alternatively run an earth wire back to the maiin fusebox or battery. Make sure its of reasonable cross section to carry the electric load. If this is all too technical get an ICE tech to fit this for you rather than setting your new wheels on fire.

 

[Ted]

Also, many systems will earth via the aerial cable.

Don't do this, as it will lead to increased interference.