turn signal problems

My fiance has a '90 Baretta and her turn signals don't work, also her emergency lights only work in the front, but not the rear. Any suggestions on what may be the cause and how to fix it?

My sister's husband tried switching the turn signal module with the emergency module, but that didn't do anything.

When you say they don't work, do they not flash or not come on at all? Assuming that you have already checked the bulbs and fuses, (and assuming they don't come on at all) check for power to the sockets. If no power at the socket, check further up the wire until you find power. If you have power to the socket, make sure the ground is good.

You have eliminated the flashers as a problem by switching them, so you should check the fuse for the turn signals (it is separate from the hazard flasher fuse).

If the fuse is intact, I'd suspect a problem with the brake lamp switch, the 4-way hazard switch, or wiring. Of those three, it would most likely be the switch.

Do the brake lamps work correctly? Including the center high-mounted lamp?

One thing you can do is exercise the 4-way hazard switch on and off for several cycles to help wipe the switch contacts. The turn signals operate through the normally closed contacts of this switch. The outer (not the center) brake lamps also route through this switch as well, so if they fail it is an indication that the hazard/turn signal switch is failing.