What, specifically, have you checked? These cars have a 'multi-function' switch........that would be the turn signal lever that has the wiper and dimmer incorporated into it. If this 'switch' starts to go bad, it can cause a myriad of problems. do your hazards work? Have you checked to see if you have power in and out of the turn signal lever? I have a Chilton's manual that has about 20 pages of wiring, so if you need something scanned and emailed I would be happy to help. I ended up having to replace mine after it decided I didn't need headlights anymore. I had to pull the switch and engineer a jumper wire to get my headlights to work. If you do indeed need a new one, 5.0resto has them for around $80 last I looked, and they are Ford parts.
Michael