I've been having this problem with my Esquire for a while. Every so often, the pickup just goes dead. It does pick up a very small amount of sound, but at least one switch position is completely silent; the other two make a tiny bit of noise. Leaving it for a while usually fixes it, though I can't say how long I have to leave it (it varies).
I thought it was wiring at first, but I've checked it and it seemed ok. In frustration, I tried adjusting the pickup height.
Then I accidentally tapped one of the magnetic poles with my magnetic screwdrivers and...BAM! Noise again. Could this be a grounding issue or something like that?