I bought a new 1988 F150 and the inspection failed because the hazard lights failed to operate, but when I push on the brake with the hazard switch on lights operate. Fuses were checked and good. Grounds were also checked and are fine. Dilemma, Please help us.

 

Check the HAZARD flasher. It's a different one then what makes your turn signals flash. Don't know where it's at.

 

While new to you, it's not exactly a new truck. I'd say it is just getting broken-in. Check the emergency flasher. It is separate from the turn signal flasher and if it fails the lights will still work for running and brakes. Also be sure both filiments in the front and real lamps are not blown. The flasher is about $2.50 at all auto parts stores.

 

I agree completly it is most likely the flasher.

Scott