bluetooth does not work

Hi Chris, you don't give us much to work with...

What's the history of the device and what happened just prior to this problem? If it came out of the blue and was working fine before then I would simply try to do a hard reset. Hold the Home Button and Power Button for 10 seconds and let the phone restart.

If the phone was dropped, damaged or repaired, then the problem is internal and hardware related but you'll have to give us more details.

EDIT

Well, at this point you'll have to open up the phone and take a look inside. This is what the Bluetooth antenna looks like. You can see it within the housing on Step 66 of the Rear Housing Replacement guide.

While there is no specific guide for changing this antenna, I would follow the Logic Board guide to remove all of the parts necessary to access it.

I can't guarantee that this will solve your problem. Otherwise, consider having a professional look at your phone to properly troubleshoot it.