Yes but if you have to ask the answer won't help you much! No offense intended. A Digital Multimeter (DMM) or ohmmeter is useful to check for continuity but you have to be able to know how the switch works in order to test it (ie what contacts should have continuity in which postions).
Moving on.....
Sure. Do you have a voltmeter? If you have a voltmeter and a schematic diagram of the switch, it's pretty easy to figure out which contacts are made in the various positions and see if it's working. Radio Shack sells some decent meters. If you're going to do wiring on a regular basis, I'd say it's worth it to spend $50 or $60 on a good meter.
thats what i thought, i read somewhere i had to use a multimeter and i have one i just dont know hot to use it. if someone can be kind enough to explain how to use i would greatly appreciate it.

You select the ohms/resistance setting. When you touch the red & black test leads together, the scale should read 0 Ohms (or very close) to indicate the resistance between the two leads is low (or good continuity). A switch contact that is closed will give the same reading and an open (or not closed) contact will give an Overload (OL) or maximum reading. Some DMMs also have a continuity tester built in with an audible beep to indicate measured resistance less than XX ohms (this setting using shows a diode symbol & ")))" symbol to indicate sound (beep). Since you're either looking for an open or short (with the switch not wired to anything yet) the continuity range is fine to use for this. Your greatest challenge is discovering what the contact arrangement is....If you can find a part number on the side of the switch or wiring diagram for your guitar that should help.
Moving on.....
Last edited by KenG at Jan 18, 2009,