I have a 1989 ford f250 my hazard lights and brake lights don't work but my turn signal and tail lights do what could it be

sounds like a wiring loom connector may have come apart as affecting all rear lighting trace loom back from light cluster to see if all are connected properly

Suspect the multi-function switch. (turnsignal) these fail a lot.

Electrical issues are always a bit difficult to diagnose. Since I have not heard the wiring harness to be an issue on these, I would first look into if there was some add on causing an issue. Did you or someone add a trailer harness? Some type of additional lighting (like an LED bar)? Even possible a radio or under dash work? If not then do a once over and look at where the wiring comes through the firewall, or through the body to feed the turn signals. You just have to systematically follow the wiring from the lights back to the switch until you find the culprit. Let me know what you find and I can try to assist further.

the rear wiring harness for the lights at the bed and bumper are either unplugged or corroded and not making contact

You may have a bad signal switch..Your brake lights run through the signal switch..Try hitting the brakes and move the switch around and see if your brake lights come on intermittently..

For 1989 Jeep Cherokee the Flasher is located:
* Front seating area, driver side, under dash, above kick panel, mounted in bottom of convenience panel for Hazard flasher
* Front seating area, driver side, under dash, above kick panel, mounted in top of convenience panel for Turn signal

Hope helps.

THE TAIL/MARKER LIGHTS, GO FROM THE HEADLIGHT SWITCH TO THE REAR FOR THE TAIL LIGHTS & TO THE FRONT FOR PARKING OR RUNNING LIGHTS. ALL THOSE LIGHTS ARE ON THE SAME CIRCUIT, { BROWN WIRE } THE BRAKE & TURN SIGNAL WIRES GO FROM THE STOP LIGHT SWITCH & FROM THE TURN SIGNAL/HAZARD SWITCH. NO RELAY IN THE TAIL/PARK CIRCUIT. CHECK THE FUSES WITH A GOOD FUSE TESTER.

replace your stop light switch its on the brake pedal

take the hazard button and tug and wiggle it real hard when pushing the brake pedal, if they start flickering, you will need a turn signal switch replaced.

try replacing the flasher first. and check the two fuses for hazards and signals.