2002 vw jetta I have brake light and signal light but on tail light

check your owners manual for the fuse location , and check the appropriate fuse for starters, and then try to replace the bulb, the guys at autozone and advenced auto are nice and should be able to help you !!

could it be my headlight switch

possibly, depending on the milage and use of the car, do the front parking lights work? they should come on at the same time as the rear tail lights, if the front parking lights do work, then it is definatly not the switch, i would check fuses first and then bulbs, you may also type in on youtube and may find some information to fix it yourself, like "2002 vw jetta tailights not working youtube" type it in google. the library is closing now and i have to leave, but i will check with you tommorow, try not to bring it to a shop, they will ripp you off if they can, unless its someone you can trust, it SHOULD NOT BE any major problem