Interesting...loss of gain + switching problems

[RGX]

Just developed a rather interesting fault in my les paul:

1) Loss of gain and tone from the bridge pickup...it still distorts but I have noticed a lack of response and more mushyness than usual.

2) When switching to the neck pickup, occasionally nothing happens, and while playing, wham, neck pickup turns on from nowhere. Didnt do anything but leave it...if I leave it for a while in neck position it will gradually come back, only to dissappear just as quickly.

I'm thinking fairly obviously that it's wiring, but what wiring fault causes this sort of problem? What should I look for? I'm also suspecting my lead, i have no other to test it with right now but can it cause these sort of problems?

[HJM]

I'd start with the switch...

[PhilKing]

I agree with Hayden, the switch sounds like the culprit.  Was it loose at any time?  If so the wires might have twisted.  I can't see why it would work if you leave it (unless the switch is still loose and the wire straighten as you leave it alone).  On a Les Paul it is easy to check the switch.  If is is a Gibson, it will have an exposed wafer switch, you need to check that nothing is going between the wafers.  If it is a copy, it will probably have a boxed switch. If so, I would change it, as you can't really repair them.

[R/2e]

A problem I've come across with the Epi LPs is where they are shielded with that black shielding paint, the switch can make contact with the paintn and give some weird results, one I fixed had a volume cut across the neck pickup. First time I came across it it drove me mad and I ended up changning all the electrics before I found the problem. The solution is easy, a wrap of insulation tape around the switch contacts.

[Baxter]

I think that you have an earthing problem.  It could be the switch or the jack socket.

If the problem occurs on both pickups then it has to be a connection common to both pickups.  

Try touching up the soldier joints on the switch, and jack socket.  Then all the other joints.

If this does not work, try cleaning the switch.  The Switchcraft LP switches can be cleaned.