Telecaster Special with output fault, wiring??

Hi,
I'm trying to fix a friends special edition telecaster, it has a single neck pick up and a humbucker at the bridge with a three position switch. But it also has a switch inbetween the knobs, so the wiring looks quite different to normal.

The problem is the volume drops, as in cuts out every now and then which gets worse and more regular as time goes on until it's completely dead. It's normally cured with a wiggle of the lead of a small tap so I assumed it was a wire/solder come loose. She has had the guitar fixed twice before by a guitar tech but the problem always comes back, they never actually tell her what the fault was only to say 'wiring & its a common fault'.

Having had a look most of the solders look in good condition including the jack wires, the only connection that looks like it has been repaired is on top of the volume knob, the two pick-up earths and a wire from the switch which I can only assume makes the humbucker into a single pick up???

Anyway I've repaired a few guitars, nothing serious so said I'd have a look and see if I can fix it. Does anyone have any ideas/things to check before I start resoldering various wires?
Am I able to post pictures of guitar + wiring (sorry new to forum)

Thanks in advance of any responses

Welcome to the TDPRI! Wiring problems like this are foten tricky to troubleshoo, but I'm sure we can help.

First, you can indeed post pictures. If you look above the editing box you'll see an icon that looks like a little square picture of a mountain landscape. That will allow you to enter the URL of a picture you have posted somewhere on the web (flickr, picasa, etc.)

If you click the "Go Advanced" button at the bottom of the editor, you'll get a new editor with more options. One of them is the paperclip icon, which allows you to attach images to a post from your hard drive. You're limited to relatively small images, though.

The problem you describe makes me think that there's a dirty contact at the pickup selector switch or jack, or inside the volume pot.

See if you can reproduce the problem, and then clean one of those items to see if the problem goes away.

A good electronics cleaner like Deoxit is best. You'll probably find it (or a similar product) at any place that sells small electronic parts for repairs. If you don't have retail places like that, find the supply stores that your electricians shop at.