1986 F150. Every light works on the truck including the hazard flashers except the rear ones. The rear hazard lights wont flash. The front hazards flash. The Rear brakes lights work, turn signals, every single light on the whole truck works even the front hazards. For some very strange reason the rear hazards do nothing when I turn on the hazards. I can hear the relay clicking, and the dash lights flash. Any suggestions on where to start looking. There was a electronic trailer brake controller in the truck. Could this be causing the problem. I took my meter and probed around a little bit but could not find anything that looked wrong or was giving me a funny voltage or no voltage. The brake controller is hooked in with suitcase clips. (the ones you smash down the metal bar to make contact on both wires) I wiggled all the wires and could not find anything wrong.

 

Make sure you are not holding down the brake pedal when the hazards are on, they won't flash if that happens.

The hazard switch is built into the turnsignal switch. Cycle the hazard switch up and down about 5 times and see if it starts working.

P.S. You need to go back to your gas tank thread and tell us what you did to fix it.

 

Franklin2- Yup you are exactly correct on the brake. If I push down the brakes the lights come on and don't flash. This is not the issue I am having. Nothing is happening in the back. When the flasher switch is on the front lights flash and I don't have any lights flashing in the back. (this might me confusing) The brake lights work when I hit the brakes, the turn signals work front and back, but no lights go on for the rear flashers. I think you were thinking the lights were just not flashing. I don't have any lights on at all, I should say no lights come on for the flashers. Like I said everything works except I get no lights going on or flashing but everything else in the back still works.

 

It has to be the turn signal switch.

If you have brake lights, and you have turn signals, but no rear hazards, then it has to be the turn signal switch itself.

The turn signal switch combine the turn/brake/hazard circuts into two wires leading to the rear of the truck. Left and right respectfully. If it was another problem besides the turn signal switch, then the turn and brake lights would be affected as well, in a similar way.

 

81-F-150-Explorer- Thanks!!!

Yes this was the information I was looking for. I was confused why every thing else works but when the flashers are turned on they don't do anything in the back. Is the switch hard to replace? Is there a way to test the switch?

 

Yes, and you did just that test. Part of the test proceedure is to turn on the hazards, brakes, and turn signals and observe what happens.

Since brake lights, and Rear turn signals are on the same circut as the rear hazards when they leave the switch, if it wasn't the switch the other brake and turn signals wouldn't work as they should. Since they do, it has to be the switch.

The front turn signals and dash indicators are isolated from the rear circuts as well. Since the front Hazards work, but not the back, that tells me your hazard circut is in good order. Has to be the switch.

The switch is moderate skill level, and requires the removal and instalation of the steering wheel. You pull the steering wheel to get at the switch underneath. The wires snake up the steering column and plug into the main harness via a u-shaped (horseshoe) connector at the bottom of the column.

 

Did you cycle the switch up and down rapidly like I suggested in the first post? It could be just a little bit of dirt in the contacts, and that would be a lot easier than changing out the switch. It has happened before. Most of the time someone fiddles with the hazard switch, and then after that some of the lights won't work afterward, and cycling the switch up and down clears it up.

 

I have been turning the hazard switch on and off about 300 times. Every time I drove my truck or remembered to try it, I turned them on. I really did not want to pull the steering wheel. After about 301 times they started working. So thanks again for the help!!!! If anyone else has the same problems just keep working the switch and it might just turn on after 400 times.