During weekend I was able to do more testing and diagnosis on issue and now my conclusion is that glow plugs are not a problem, they only make main issue to appear. Main problem seems to be the main fusible link. That one from battery to fuse box. It seem to be weakened or half broken or something like that and thus I was uneble to test it. From what I read its best to take it out and test it outside of vehicle AND replace it while at it. But during my testing and after evening of thinking it all makes sence.

Lets start with simple thing like a clock, why that did went out and what that has to do with starting or glow plugs? Well, nothing since clock's memory is powered throug Dome fuse and there are no switches or relay. My measuring showed values between 0.7v-3v at dome fuse when truck 'died' but battery volatege sits at nice 12.6v. Only important thing between battery and dome fuse is fusiable link. This volatege drop could been observed on interior lights. They did not went out completly, bulbs were still glowing a little bit.
Why flasher went crazy when I did try to turn on hazard lights? Wrong volatege most likely due to voltage drop at fusible link.
Why all worked okay when engine was running? Alternator provided direct power and fusible link was used only to charge battery at that time.
And finaly, what glow plugs has to do with that all? Most likely GP's high current draw thourh weakened fusiable link crated big voltage drop there, cutting all power to truck. This voltage drop did make GP timer and relay to turn off, killing high current draw, removing voltage drop, that makes voltages go back to normal, that makes gp timer to kick back on, crates high curent draw, makes voltage drop, makes timer to turn off.... see? that is whole crazy relay clicking thing.

Now I did fix it by 'taping' on to fusiable link, since them its fine. What a fix That also explain why wiggling ground wires helped in past and why cleaning battery terminal helped -> actualy me working around fusible link and moving it around helped most likely.

I will be replacing fusible link. Sadly fusible link do not exist in this part of world somehow, so I will be replacing it with 80A MAXI fuse. Then I ll see if that fix it for good or not.