Hi Hugh, if you are just replacing a p/u, and I take this would be on a Strat style guitar, you would have to remove the pickguard screws and lift up the pickguard enough to get to the p/u's, usally the wires going to the output jack are long enough you can do this without disconnecting them, remove the 2 height adjustment screws and springs, desolder or cut the wire at the 5way switch, the ground wire should be soldered to the back of the vol pot, remove the ground, mount the new p/u ,cover,springs and screws, solder the hot wire back to the switch and the ground back to the pot, replacing everything with the pre-wired assy, requires the output jack wires be desoldered from the old assy, and resoldered to the new assy. Doing this kind of stuff isn't too difficult, if you put everything back the way it came apart, soldering is a must do kind of thing for all guitar electronics, ..............