My car will not start and when I turn the key forward to a certain point the 5 pin main relay starts clicking rapidly and the automatic transmission shift lever solenoid goes crazy with the plunger going in/out rapidly also the dash lights start flickering. There isn't any power to anything else and when I tried turning the headlights on it start making a weird buzzing noise without the lights coming on. So far I've replaced the main relays and ignition switch with no results.

 

Anything recent on this car that was done, or did this just start one day?

clean battery terminals and connections to the main fuse panel
check all grounds for corrosion
load test the battery (or try with booster cables)

It actually sounds like the battery is dead, not in terms of voltage but in terms of amperage capacity. But the symptoms can be any of the above ^^

 

It just started one day, the battery is fairly new and the terminals don't have any corrosion on them. I checked the battery and it's still good, I even tried jumping it just to see what would happen and it didn't help.

 

Ok, do a voltage drop test to the starter. Maybe the starter is shorting out. This is assuming you KNOW for a fact the ignition switch is good! Otherwise, if you aren't sure the ignition switch is good, then really the ignition switch is the top suspect.