Hi guys how do you know when a pickup is broken ?? one vintage noiseless pickup that I have has extremely low output wayyy lower than the other two pickups , I have to play it with overdrive to hear it because on clean it is almost imposible to hear...... I have checked all the wiring and nothing seems to be loose or anything like that... is there a way to cofirm if the pickup is broken? thanks!! ....

First, you have lower output is the pickup is lower than the others.
Second look for problems with the wiring.

Rule of thumb;
1. No output.
- either your pos is shorting or disconnected totally.
2. Very low output.
- bad pos. connection.
3. some noise, especially when touching the poles.
- loose neg connection.
4. a lot of noise.
- no neg. connection.

As rdclmn7 said, the first thing to check is the height of the pickup and/or check/recheck the wiring. Please note that a wire doesn't have to be "loose" to have a poor contact. You can't always just look at a wire or contact to know whether it's bad or not...you may need to actually test the connection for continuity. You'll also want a wiring diagram/schematic to make sure that it is in fact wired properly to begin with.

If you have checked all of that and you still can't find the problem, the one way to test the pickup for sure is to snip the lead and measure it's resistance. If I remember correctly, VN's for Strats usually measure at around 9.8 k ohms...if the reading is significantly higher or lower, the problem is the pickup. It's been a while since I've done this sort of thing but I think a broken wire will read as "infinite" resistance and a shorted wire will give you a very low resistance reading.

Good luck!
Jim