1995 Ford Fairmont highbeam headlight flickering

My high beam headlights flicker after they have been on for about 5 mins. Sometimes they make all the lights drop out. I have tried relay switches and fuses? Any suggestions?

Also I have used this vehicle for towing a horse float. When I am driving the gears jolts as it changes. Once it is going it is ok but If I slow down/stop or speed up it dosent change smoothly.