Tailights and cluster fuse keeps blowing, help me, id sincer

96 s10 blazer 4 door 4.3l v6 156000 miles

a few weeks ago the dash lights in my 96 s10 blazer 4.3 4 door went out. The tailights also blew. I replaced the fuse "pk/lps" and it worked fine for a day and then it blew again. I replaced the normal 20a fuse with a 30a and it still continued to blow. I took it to the dealer and they kept it for a week and still could not fix it. As soon as I start to drive about two minutes later the fuse blows. Ive checked both the headlight switch and the interior light dimmer switch both seem to not be making the problem. All the connectors seem fine. I need some help and I know you guys probably can help me. Anything will be greatly appreciated