Long-time reader and participant here, though I admit it's been a while, which is pro'lly why my account got deleted. On with the show!.......

My father's 1982 300SD's locks stopped working last week. I hear about it now. So I go to the trunk-mounted vacuum pump and throw the meter on it. I did some reading here and she IS getting voltage at the right pins for up/down but yet the pump doesn't seem to activate/work at all. I also removed the single vacuum hose to it to bleed off any pressure that might cause this problem, but that didn't do anything. When does the pump actually activate(work)?