headlights

When I turn on my headlights they flash on and off I can only turn on the running lights I have a 1993 thunderbird

Do they flicker after they have been on for about 10-15 minutes? You may want to contact your local Ford store and have them look up your vin on Oasis and check for the ever so common headlight recall. If it affects your car and has not been done, it will more than likely fix your problem.