Hi,hows it going.I am new here but have got info here for a while and I gotta say the site is great.Anyway,I lost my high beam on the driver side today,(98 Cavi,4 door,2200 eng)and I couldnt see why.The bulb was good and the grounds are good so I looked around and it turned out the wires going into the socket were totally corroded inside the plastic covering.A simple twist and the wires broke off about an inch behind the socket,in my opinion GM shouldnt use such thin copper wire,it just sucks.Anyhoo,I hopes this helps,cos sometimes figuring lights out can be a real pain .Take care.