BMW Repair: need help, ground circuits, fuel pump relay

Question
i have an electrical problem with my BMW 325es 1985. sometimes the secondary fuel pump works and sometimes it doesn't. we first thought it was the fuel pump relay, but we are not sure. my dad and me took a good look at it and we jumped the relay and sometimes we heard the pump turn on and sometimes it didn't. please help!!!!!

Answer
Your first step would be to check the wires going to and from the pumps,the ground circuits and those around the battery.The ground often turns green on the braided wire and that affects the body ground as well.The wires turn green internally(under the casing)it can be noticed by a bumpy spot in the wire.This is a real common fault especially being 24 years old.So really look at the wires and the grounding points.