This is a basic tutorial that I am posting because a few weeks ago, I had no idea how to do it myself and posted this up as a question. So now, I am learned the answer and want to add to the board and share knowledge with the hopes of helping others....so all that aside, here goes:
You will need:
1) A Multimeter that measures DC Resistance, in Ohms, with a sensitivity level/setting that will test between 1k and 20k (this should be a good range for almost ALL pickups)
2) A Pickup with the sheilding wire pulled back so that the hot lead wire is exposed - Depending on the type of pickup and wether or not it is a 4 wire for splitting, the hot could be several different colors. Below is a chart of what I have found is the HOT for different makes/models:
A) Vintage Dimarzio (without 4 Wiring): WHITE is the hot lead
B) Vintage Dimarzio (with 4 Wiring): RED is the hot lead
C) Vintage Ibanez (without 4 Wiring), ie Super 70s or V-2: WHITE (although, I had one rare one that BLACK was the Hot lead)
D) Seymour Duncan: BLACK = Hot
E) 80's Kramer Pickups: WHITE = Hot
F) New Dimarzios: RED = Hot
I have never used active p/ups ie EMGs, so I cant really answer on those.
3) Your leads should ideally have alligator clamps rather than the needle test leads so that you can get a steady reading (See PICTURE 1)
A) Connect the test leads to the meter FIRST BEFORE connecting them to the pickup (circuit) being tested. Check your manual for where the black (ground) lead is inserted in your multimeter and where your Red (positive or "Hot") goes in the meter.
B) Set your meter to the 200 Ohm (NOT 200K!) range and touch the Red & Black Leads together to make sure you have a good connection; it should typically read between 0.2 Ohms and 1.5 Ohms; if it reads MORE than 1.5 Ohms, you have a bad connection and need to check:
1) if your leads are inserted properly
2) if your leads have a short in them; if they do, you need to replace them (SEE Picture 2)
C) Set your multimeter at the 20K setting for resistance (look for the Ohms symbol, the upside down "U" looking symbol which is used for measuring the resistance of a component in an electrical circuit); it is best to start at the highest and work down, although since most multimeters go from 20K to 2000, 20k setting should work. IF A "1" APPEARS ON THE LEFT SIDE OF THE MULTIMETER, THEN THE METER IS SET TO A RANGE THAT IS TOO SMALL FOR PRESENT MEASUREMENT BEING TAKEN; INCREASE THE SETTING ON THE METER UNTIL IT DISAPPEARS! (if it doesnt disappear after all settings are tried, either try re-attaching your test leads or perhaps your meter doesnt have the proper range to measure the resistance; it is most likely the former when checking pickups, so fiddle around with your test leads)
(See PICTURE 3)
D) Now, connect your black or ground lead to the brass base plate of the pickup (you can also connect it to the ground lead coming out of the pickup, but for simplicity we will connect it to the base plate (See PICTURE 4)
so that you dont confuse the color leads coming out of the pickup, although if you really want to go for broke, on a four conductor pickup, it will be the one that is NOT soldered/fused together and is most likely paired up with the BARE wire (See PICTURE 5)
E) Connect your red lead to the pickup "Hot" (see #2 above for a list of colors for hot leads for several types of pickups) (See PICTURE 6)
Your pickups resistance should appear on the meter!
F) IT IS A GOOD IDEA TO USE A PICKUP THAT YOU ALREADY KNOW THE RESISTANCE OF FOR THE FIRST TIME YOU TRY DOING THIS SO THAT YOU KNOW YOU HAVE THE METER AND LEADS RIGGED RIGHT! For example, if you have a new Seymour Duncan '59 BRIDGE P/UP, from the S/D website, that pickup should read at about 8.13 k.
Note that the final shot is an old DiMarzio "Super Distortion" Pickup from the 70s; I think that it is actually a "Dual Sound" model b/c of the 3 conductor wiring ala Al DiMeola; average DC resistance for these models was between 13.13 and 13.70 - Not a "HOT" pickup by today's standards where some of the hotter ones top 16k!
I hope this helps and shoot me a line if you need more help.