Hey fellas, 78 K5 400sb The pressure gauge is fluxing real bad sometimes drops straight to zero! I already changed the pressure switch... and it is still doing it. I have heard of galley seals that come out and can cause this problem... just wondering if they are hard to replace. I am dropping the pan tomorrow to check that and the oil pump. Just curious if anyone has any inputs on what they think it is. Problem #2 I turn on head lights, gauge lights are off, and the floor light comes on until I turn the upper interior light on (turning head light switch). then it goes off, but still no gauge lights. Appreciate any inputs on these issues.