The brake lights in my 1990 f150 xlt 4x4 aren't working so I checked the fuse & bulbs.... they're both good so then I changed the switch on the brake pedal & still didn't work.... I read on another post about the brake/hazard flasher on the fuse panel so I checked the hazards & the back passenger one flashed but driver side didn't so I wiggled the hazard switch to see if there was a lose connection in it and when I turned the hazards back on niether of them flashed. so I then bought a new hazard flasher for the fuse panel (which it goes on the back right behind the turn signal flasher) and when I went to pull the old one out there wasn't one in there so I put in the new one and the hazard on the passenger side (back) started working but not the driver side & the brake lights still don't work..... Any help or suggestions would be great!

 

Get a test light or a DMM and check for voltage at the bulb. If there is voltage you need a bulb or have a bad ground. If not check back at switch, flasher,and fuse, and the brake light activator on the pedal. Just look for the place where the electricity stops.

 

My friend had the same thing happen...... It was the multi-function switch that controls the blinkers, wipers, and hazards.

 

Does anyone know how to replace the multifunction switch in a 1990 f-150?

 

no multi function switch on the 1990.
the are on the 92-96 models.

 

Have you checked for voltage yet?