I got my hands on this used GrassRoots G-CL-60I recently!

The problem is that there is a 3-way toggle switch that basically controls the KNOB and shifting it in 1-2-3 are supposed to turn the KNOB into VOLUME-TONE-TONE respectively but my repair guy ran out on me and now I can't fix it. Can somebody please help and provide me some wiring diagram or draw my a rough sketch so I can hook it back up myself.

By the way, 3-way switch has 6 terminals on the back (3x2) design so let me know how to hook it all up!
I have no idea what your trying to say. Are you saying the switch changes your knob functions?
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yes, exactly! it is supposed to but it won't cause the wiring is all wrong.
Best advice I can give you: email ESP and ask them for the wiring diagram. This seems surprisingly complex, so getting the proper diagram is best.
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I'm still a little confused about what this switch is supposed to do.

you have 3 pickups, correct?

a 5-way blade style switch lets you choose the normal strat options (bridge/ bridge+middle/ middle/ middle+neck/ neck) ?

there's one pot, and one 3-position toggle switch?

if that's all correct, what is the 3-position switch supposed to do?
from the OP, it sounds like position 1 of the switch makes the knob act as a volume. a master volume, I would assume?

position 2 and 3 both make the knob act as a tone pot. but a master tone? neck tone? bridge tone? ..what're each of the positions supposed to do?
if you don't know, and aren't able to find out, what do you want them to do?

we can help you re-wire, but we need to know some more detail before we can really give you afinal answer
exactly.. it has a 5-way for the pickups...

then a pot and a 3-way and is supposed to do the same you wrote.
3 positions are supposed to act like VOLUME and TONE and TONE. one is supposed to be the master volume. i don't know much about whether the other 2 are the neck/bridge or master tone.
^then it's a little tough to help you wire it up :/

try emailing ESP as brock said, they'll be able to give you something you'll be sure of.

otherwise, what would you like it to do? ..you don't necessary need to re-wire it to match the stock wiring. you can do whatever you want with it (..well, almost)
then i would like to rewire..

i have three single coil pickups, 5-way pickup selector switch, 1 knob and a 3-way toggle.

i want the usual pickup setup:
1 - bridge
2 - bridge + middle
3 - middle
4 - neck + middle
5 - neck

and i want to setup the 3-way so that:
position 1 (up): something like a killswitch
position 2 (mid): master volume
position 3 (down): master tone

off the top of my head, I can only think of ways to make it work as volume/useless position/tone

I'm at work, so I cant really spend tons of time trying to figure it out the way youd like, but post in the wiring diagram thread, and someone might be able to get it worked out for you, if it's possible.. :/

and your switch probably works like a normal on/on/on toggle switch, but do you have a tester of any kind, to make sure it works the same way?