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It's not a relay - it's a flasher unit, and it's the same as the one for the turn signals. The hazard flasher is on the top of the dash fuse block (inside the dash) and is rotated 180° so its terminals don't hit the turn signal flasher terminals.
Can you hear a click when you push the hazard button in? What happens when you press the brake pedal?
I was also looking for that dang hazard flasher on my 89 F150 .. have read all the threads and Haynes, but I'm still not sure where it is. I followed the clicks with it turned on, and it seems to be behind the dash just to the left of the glovebox ... where Haynes indicated.
So i removed the glove box door, but the thing is, it doesn't look like the typical round flasher units ... just looks like a squarish connector and I can't get it disconencted.
Is this a permanent device, or am I barking up the wrong tree?
The turn signal flasher was easy ...right on the fuse box, lower right. I replaced the old one with an electronic heavy duty for running my trailer lights.
CORRECTIONS> The hazard flasher seems to be in-dash to the RIGHT of the glovebox (not left); and the turn flasher is on the lower LEFT of the fusebox (not right).
Checking back .. anyone know the location of hazard flasher on 89 F150? Turn signal flasher is on the fuse box, but when I follow the sound of the hazard flasher (behind glove box), I can't find it -looks like its permanently wired in.
I'm having the same problem locating the flasers for my 1990 f250. Just foung what might be it. Took off the glove comp., and to the right there was abrown, square part with 4 wires running to it. Ripped off the retaining clip( if i can't see it dnglign, it makes no difference to me) and disconecteed the harness. Running to Pep bOys now to see if I can sort this thing out. Will let you know how I make out.
I got it. THat squarish brown thing is some sort of relay, maybe to that annoying buzz, or at least that's what the pep boys guy told me. But we found the hazard flaser right next to it. It's on the frame between the glovebox and the doorwell/fender. mine was green, with the wires towards the glove box. It feels like there is a screw holding it on, but it is actaully just a nipple on it. I didn't get it off, the PB guy did, but I think he either turned it, or riased the whole thing up or down. I replaced it with a Tridon #552, and they work now. Surprised pep boys came thru? Me too.
Does the turn signal flash on both sides. They will illuminate but not flash when a bulb is burnt out or corruded up. Could be same on hazards. I always use HD version of flasher when I can find it. Could be not enough voltage going to hazard flasher. Does lights brighten when you turn off hazards? Check that all brake lights work as well.
They all look good to me. I even replaced the front bulbs becaused I noticed the top filament were gone. The previous owner hooked up trailer lights himself, I know becuase he has the taillights spliced, with extra wires running under truck. He also put the trailer lights on a toggle switch in the cab, as well as a toggle switch for the outside handle lights. I'm wondering if this has anything to do with it. Sucks, because I really don't want to take it somewhere to spent mo money for a simple fix.
Things to look at would be the trailer park (clearance) light wire and both turn wires and brake light wire(s) for short to ground. These should blow a fuse though unless a larger fuse has been used. Sometimes the light sockets get worn, taillight and front, and don't connect good to the bulb. I'd check for voltage and ground there but if the light works, you already know that. The taillights have seperate circuits for turn and stop though. It could be that the trailer turn/brake lights have been spliced into the wrong circuit. It'll take time with a test light or voltmeter but won't cost much. I generally use Hoppy or similar plugs for trailer connections and avoid miswiring and splices in general. I'd just pull the trailer plug wires and replace with the plug in type for <$20. You still have to ground the white ground wire somewhere on the frame and it's easy enough to find a screw/bolt/hole to put it. Good luck.