All lights work on my 92ford f250 brake lights don't work new brake switch,signal switch,bulbs check the fuses they good no brake lights still

any truck that old is super hard to find schematics
to simple voltmeter checks find this cause.
fuses, switch, wiring, and lampsl
fuse = haz/stop
goes to stop switch
then stop sw output pin red/black
goes to DIRECTIONAL switch
if wiring is good and any trailer hitch wiring mess is repaired, then this switch below is bad.
brake wires is GREEN I think. see it?

Check your brakes lamp switch

Well you missed something .Let me ask you this what wasn't working before you replaced the multifunction switch.
The brake lights if the blinkers the running lights the head lights int lights all work must be the contact point or switch at the brake padal or a ground issue to the bulbs or the bulbs are incorrect Ford has this issue with the bulbs they look the same but there not check that for the brake lights .
I have had the same problem the lights work they done work correctly and its hard to tell .Make sure they are the correct bulbs

You mean the brake lights don"t work ? Do you have power in and out of the brake switch ?

Do you have power going into the turn signal switch from the brake switch, and then coming out to go to the lights ?

Well the brake light and turn signal circuits are on two different fuses, but they both go thru the turn signal switch.
So I would start by checking for power in and out of the turn signal switch for each circuit.

You either have a bad brake light switch or a bad fuse that powers your brake lights. Go to your fuse panel and check the fuse first. If it checks good then check the brake light switch. The switch will be located on the brake pedal at the top. There should be two wires into the switch. One will have power at all times. as you depress the brake pedal it makes the connection in the switch to the other wire which then sends power to the brake lights and illuminates the bulbs. Use an electrical tester to make sure you have power in and power out when the brake pedal is depressed.

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..

The third or High Mounted Brake Light runs straight off the brake light switch on the brake pedal arm. You say you tested the "brake unit"? I assume you mean the third brake light assembly, and if you get power there when someone steps on the brake pedal, then the bulbs are bad.

The power flow for the brake lights goes like this: Fuse ->Brake switch -> Turn signal switch -> Rear lights. The only difference is, if you have a 3rd brake light in your rear window, that gets its power directly from the brake switch. It does not go thru the signal switch first. So, if you are having a brake light problem, and your fuses are good, check the 3rd light in the rear window, if it lights up (assuming the bulbs are good, no one ever changes them), then the problem is most likely in the turn signal switch, hope this helps!

you don`t say if its both or just one brake light out.you say the light itself is on but not if you mean tail light or what.the tail lights use a different filament in the bulb than the signal light which is the same filament that the brake light uses.if the signal light work on the rear then the bulbs are good,if just one side works then the bulb is no good on the side that doesn`t work.if the signal lights work but neither brake light works then you need to check the fuses in the fuse panel under the dash on the drivers side.if the fuses are good then it will be either a bad wire at the brake switch or a bad brake light switch,this is located on the brake pedal lever under the dash.