So my final update on this "small" problem of mine that took more hours than excepted. Now starter works when turning the key =)
So what did I do? Change the positive cable going from the "buss-bar" to starter since the old was a mess. This did not help.
Changed main cable from battery to Switch on-off/buss-bars and also took of all cables from the buss-bars and cleaned them properly since they had corrosion (copper green white stuff) and mounted all cables back again. (will change cables in a few days to new tin covered)
Turned the key and the starter made the most beautiful sound I have heard in a long time. Think the neighbors heard the scream of joy =)
You can not always trust the multimeter! Next will see if there is a in neutral switch by turning key in while in gear. If it turns will have to install one.
Thank you all for your help!