2. I have used 50w 6 ohm resistor just for rear indicators (because indicator relay was clicking too fast) insufficient resistance on circuit.
Okay, now I understand. This makes perfect sense.
Is there more than one "earth" negative -12vdc joint? Because at the moment i can find only single negative to earth/chassis connection close the battery.
There is only one connection between the battery negative pole and the chassis. There is a joint fixed to the wire which connects to the chassis. The wire then goes to the starter- motor. This connection is also a source of troubles. In many cases, a cleaning of the contact- surfaces may help. In my car (230 type) this thick wire was broken (70 mm²). The troubles I've seen where similar, but the voltage dropped in the whole system to 8 to 9 volts. I cleaned the surfaces but this didn't help, I had to replace the wire. To test this connection, use a jumper- cable between the negative pole of the battery and the chassis. If the voltage drop disappears, in most cases the joint to chassis is the source of the problems.
There is another negative (ground) joint beyond the dashboard which connects many negative wires of the devices (heating-fan, dash- board lights and so on) with one screw to the chassis. I've read that this joint sometimes also makes troubles. A cleaning of the surfaces should help.
Regards
Hanspeter