Ford Power Stroke Nation banner

1 - 9 of 9 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter #1
I have a 1997 f350 7.3 l power stroke and the hazard lights, blinkers and brake lights quit working all at once. I checked all fuses and cb’s, all good. I’m looking for the hazard light relay and can’t find it. Does anybody know where the y hid this thing?
 

·
Registered
Joined
·
5,747 Posts
It is right behind the turn signal flasher in the fuse panel inside the cab. You have to reach up from below to get to it.

But if the blinkers quit working I doubt that it is your problem unless the hazards work and the blinkers don't.

I would bet that it is the multi function switch on the column.
 

·
Registered
Joined
·
3 Posts
Discussion Starter #3
Thanks, I think you’re write, I played with the turn signal lever after awhile and turn signals and brakes lights started working again, but if I push the hazard button they go away again, mess with the lever again and they came back. Hazards don’t work at all, I’ll look up there again👍
 

·
Registered
Joined
·
170 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter #5
Thanks, found the flasher a couple of days ago, replaced with a known working one. no change. Book says there is a relay up under the dash, still can't find it. Bought one, so I know what it looks like, but they hid it well.
 

·
Registered
Joined
·
5,747 Posts
It is on the back of the fuse box right behind the one for the turn signals.

I don't know if you can even see it. I have use the blind touch and feel to replace them
 

·
Registered
Joined
·
170 Posts
Book says there is a relay...
What book? It's wrong, or you're misunderstanding it. There is no relay in the truck's lighting systems. Only on the trailer adapter, and those relays are in the PDB under the hood. Post a photo of, or link to, the book where it describes this relay.
 

·
Registered
Joined
·
5,747 Posts
For most intents and purposes a flasher is no more than a relay that is wired to break a contact internally when power is supplied to it. So once power is supplied to it the contacts close, simultaneously a second sets of contacts open the power to the coil which turns it off. This will repeat until the power is removed from the circuit.
 

·
Registered
Joined
·
170 Posts
A relay takes a low-current input (trigger) signal, and applies it to a high-current circuit; thereby "relaying" the signal. Nothing at all like a flasher. And your description is of a common magnetic relay or a solid-state flasher; not a common thermal flasher as Ford installed on these trucks. The closest thing to a flasher is a self-resetting circuit breaker, when it's overloaded; but the flasher is designed to be "overloaded" all the time. It has only 2 terminals and only 2 internal contacts, like a breaker. Most are normally closed, with one contact mounted to a bimetallic strip (which is also a resistive shunt) with a fine heater wire wrapped around it (in electrical parallel to the shunt). When voltage is applied across the terminals, current flows through the contacts and the heater. When it gets hot enough (after a designed time), the bimetallic strip bends, snapping the contacts open, which stops the current, and allows the heater to cool. When it gets cool enough (after a designed time), the contacts snap closed, and the process repeats as long as voltage is applied. Subtle design features cause flashers to NOT be as sensitive to ambient temperature (flashing faster in cold weather) or to the number of lights they control (flashing slower when some bulbs burn out).

Crack one open & look inside.
 
1 - 9 of 9 Posts
Top