When I try and turn on my high beams on my 85 GMC truck, both the low beams go off and the high beams dont come on. (My truck has 4 headlights, and I assume the two top ones are the low beam and that the high beam should have all 4 on.) The high beam indicator doesnt come on either. Any thoughts? Also it has a chev 400 engine. Where is the distributor hold down bolt? I can turn the distributor by hand.