Yesterday I accidentally spilled a few drops of water on my GPU (MSI Geforce gtx 970 4 gb). Since that my computer short circuit everytime I power on my computer with my GPU pluged in, but works fine without it. I later found out that it's only the 6 first pins in EPS that are "broke", because if I only plug the last 8 in the computer start normally and the lights in the GPU turns on, but still got no signal to the monitor. Hope you guys can help me out. Thanks.
You've damaged your video card. You need to replace it.
Board level component repairs are off-topic on this site. However, the fact you're asking what to do implies such a repair would require skills you don't currently have, so an answer of that sort probably wouldn't be helpful to you anyway.
I'm sorry this happened to you. Next time try to keep the water away from the electricity!