1985 F250 4x2 with 6.9 diesel eng.

#1 - Turn signals.

I was driving down the road, with a trailer attached, and suddenly my turn signals quit working. My hazards work, but no turn signals at all (no clicks from relay either). Unhooked trailer, and still have the problem.

I replaced the relay, and still have the problem. I checked all my fuses, they are all good. I checked for power at the relay on the fuse panel, and I have it. This leads me to beleive that the problem is with the actual turn signal switch on the steering collumn. Anyone have any ideas on how to diagnose that without having to rip the steering wheel off and access the actual switch?


#2 - Trailer brake wiring

When that first problem happened, I used my hazards for turning. This led me to an interesting discovery. Everytime the hazard lights would illuminate, my trailer brake activate. My trailer brake works fine when I just hit the brake pedal, but it seems where I tied the wire into the truck wiring harness has it tied to the brake light (which is also used for the hazards).

On the brake pedal, there are two wires that come right off the pedal. Is this as easy as me choosing the other wire? The wire diagram in my manual isn't very helpful to me on this. Can anyone tell me where I should attach the trailer brake activation wire so that it only engages when the brake pedal is pressed?

Thanks in advance for input on either of these issues.

 

Sounds like they did the hazards things as if you think about it when you see a large truck hauling a huge load say a wide load they will have there lights flashing? That would probably explain why it works with your hazards on? I would trace the pins on the trailer wiring harness / connector on the truck. You can get pin outs for the connectors to see where they should go and then hook it up correctly i would assume.

 

The brakes come on with the hazards, because that's the way the hazard switch is wired. The brake signal and the hazard flasher use the same common wire to the turnsignal switch. Thats why if you turn the hazards on, and then hit the brake, the hazards will stop working till you take your foot off the brake pedal.

For your turnsignal problem, the first thing to check is the brake lights, since they also use the same wiring and the same bulbs as the turnsignals, and both go through the turnsignal switch. Do both rear brake lights light up correctly when you hit the brake pedal?

 

Just thought I would do a quick update. To test the switch, I disconnected the grey connecter for the turn signal/hazard switch. I then jumpered across from the relay hot line, to each individual turn signal line. When I did this, the turn signals worked. The problem was the switch. A new one cost me 50 bucks from O'Reilly, and I'm back on the road with working signals now.

One lesson learned ... the O'Reilly steering wheel puller is a piece of crap. I stripped it out rather than pull the steering wheel. I ended up using pry bars and a hammer to ease the steering wheel off.

As for the trailer brake problem ... anyone have any ideas on how to make the brake controller not work when the hazards are on? Sounds like I may be stuck.

 

If you could mount another brake switch onto the brake pedal arm that is seperate from the original switch, you could feed it 12v, and send that signal to the brake controller, and that would eliminate the problem.

One problem that would cause I just thought of; when you reach down and manually actuate the brakes by the controller switch, it turns the brake lights on. If you did the above mod, I think you would lose this feature.

 

A diode in the wire from the brake light switch to the lights should stop the power from backfeeding the brake controller. I just wouldnt turn the hazards on with a trailer unless I was parked.