1987 GMC electrical problems

[westcasey]

I've got an '87 GMC 1500. I am having some weird electrical problems with it. First. the radio doesnt hold memory; every time you turn off the ignition the clock and presets clear out. Next, when you open either door (when the domelight button is released) the radio goes off. And..... When you honk the horn I get no sound except for a buzzing when the ignition and the radio is on; the horn will also make the domelight come on. Anyone have any advice where to start looking??? Any input would be greatly appreciated!!!