W900 light issues

Hi everyone. Does anyone have a wiring diagram for clearance/marker and tail/running lights to trailer? I have an issue with it. When I turn the head lights on- buttom trailer lights come on as well and then I hit tail light switch( the very right one) - nothings happening. I drive like that for some time(10-30-50 mins) and they come on as well. Sometimes not and I have to turn all lights of and try again. Sometimes when turning headlights on buttom trailer lights trying to come on and go of right away(like blink)... and I thought may be relay is bad so I changed all off them and fee extra(5),also I changed all 3 switches for headlights,trailer tail lights and another one. It didn't help.interesting thing is- I have to turn the lights in one special order from the left to the right,If I hit one in the middle then others no lights on trailer at all... so guess someone splice the wires and made some changes. Another stupid thing-2 relays socket in engine compartment are empty and both connections are melted. I know one os for trailer abs( I had to rewire it as it's been partially cut out ) and the second relay socket(according to sticker on it-trailer stop lights) is melted a little and someone throw the relay away and put a piece of solid wire to short the wires without relay... so my guessing is that clarence and tail/brake/running lights are all on one breaker now and that's probably why it dont come on as it too much load or shortage somewhere as I have to hit the switches in special order) so may be someone have a diagram or been through something similar? Just want to try to fix it proper way instead running new wires and relays... would really appreciate any help and advice.
And last thing I forgot to mention one of the dash switches has a voltage. What i know kenworth control lights through the ground (tail lights,very right switch) thanks in advance

 

Forgot to mention its 98 kenworth w900. 775052 last of the vin