[TimV]

Alright!

First part is in, and YES it is the coolant heater itself!

I have an amp meter, so i will try the glow plugs one by one out when the engine is ideling (14,5V) and see what Amps it draw, then count them all up

I think it will be arround 11-12Amps each, making it 500W @13,5V (lower Volt because the higher load on the alternator and losses in the cables)

I have had thouths about laying cables directly from the alternator to the coolant and oilpan heater. So the stock cabeling isn't touched. And lay a bridge from where i split the big diameter wire( where i seperate wires to the loads for heating) to the main stock fuse box. I readed somewhere that you can minimise electrical losses by upgrading the big wires,