Starting problems on 2000 Venture

Primarily while on a short errand when I try to start my van the lights and bells work, but the engine does not turn over. There is no clicking or other noise. A new battery didn't help. A few times I shook the battery and the van then started. I replaced the starter, as the solenoid seemed to be the problem, and it solved it for three months until last week. I replaced the starter again and will see if the problem continues. Has anyone else encountered this problem and have suggestions?

check the conn from the pos batt to the relay fuse box right obove the batt, there is a red cover over it. remove the nut wire brush the crap out of it get some dielectric greese and re tighten the nut should fix the prob..............