Electrical problem with my 1994 S-10

Hi I think i'm stuck with a electrical problem. My accessories does not work. When I put my night lights on ,the both signal lights goes bright in my dash (but still working) and the drivers side light is lower than the passenger one. Every time I push on the brakes or flasher or wipers or just open my door my radio turn off and on again and drivers light is going low and hi. Normally when you turn the key once the radio is working, but to have it working I have to put the key on. oh yea forgot to say that my speedometer and my gages arent working to. But 2 days ago i was driving on the hyway and every time i was turning the weels or pushing on the gas everyting was working even my speedomeer and it never worked since i bought that truck. can somebody help me i don't know what to do anymore. I've checked and checker without solving the problem
thank you very much for your help ;)