Hazard light circuit wiring tip (2 Viewers)

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I just installed a universal "ez wire" wiring kit in my fj40, with great success.

1968 fj40.

Hazard light circuit tip:

In order for you to utilize the original hazard light switch you must do the following:


The universal wiring harness (ez wire, painless, or the like) runs power for hazard lights from fuse block through hazard flasher then to hazard switch.

This will not work.

You must modify the circuit.

Power must go from fuse block to hazard switch without going through flasher unit first.

From the back of new fuse panel cut the two wires on the back of hazard flasher unit. Leave enough on flasher side to re attach different wires from switch.

Attach the two wires together (this will send power to hazard switch without going through flasher.

Two new wires must be run from switch --back to flasher unit on fuse panel

Four new wires must be run from hazard switch to your lights that you want to operate when hazard switch is activated.

I spliced them in at the turn signal switch connection.

Here are some pictures. It worked!

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This is perfect timing. I have a Painless wiring harness in my 80 FJ40 and my hazards are not working. I suspect it was not wired correctly when originally installed. I will use this info to correctly wire my truck.

Thanks!
 
Question....is the hazard light circuit/switch different on a '68 vs '80 FJ40?
 
Question....is the hazard light circuit/switch different on a '68 vs '80 FJ40?

Did you get it working? I am installing an American Autowire harness that I set up in my '70 FJ40 into a '79 FJ40. I did not have a hazard switch on the '70, really jury rig wiring which is why I replaced it. The '79 has a hazard switch and I would like to have those lights. So I'm curious if you did what the fellow who started this thread did.
 
I am trying to do this right now but had a question. Do you know if this is running through the stock turn signal switch?
 
the hazard switch and turn signal switch share a circuit - find the correct OEM wiring diagram for your year cruiser, and then recreate the parts that are not present in the Painless kit - it's not painless, but can be made less so by liberal use of the multimeter

Toyota wiring philosophy is to complete circuits to ground in the switch, while domestic (Painless, Autometer, EZ-wire, any US aftermarket harness) philosophy is to provide power in the switch - the theories collide in the hazard switch circuit
 
the hazard switch and turn signal switch share a circuit - find the correct OEM wiring diagram for your year cruiser, and then recreate the parts that are not present in the Painless kit - it's not painless, but can be made less so by liberal use of the multimeter

Toyota wiring philosophy is to complete circuits to ground in the switch, while domestic (Painless, Autometer, EZ-wire, any US aftermarket harness) philosophy is to provide power in the switch - the theories collide in the hazard switch circuit
Thanks, that is a "tip" that I will keep in mind.
 
A week into switching the American Autowire harness from the blue '70 to the red '79. Two lessons learned. 1) If you are happy with the wiring harness in the one vehicle, leave and buy another one! 2) Never, and I mean NEVER, put an aftermarket fuse panel where the OEM unit was mounted. There is just no room.
 
A week into switching the American Autowire harness from the blue '70 to the red '79. Two lessons learned. 1) If you are happy with the wiring harness in the one vehicle, leave and buy another one! 2) Never, and I mean NEVER, put an aftermarket fuse panel where the OEM unit was mounted. There is just no room.

Here is where I put mine...
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A week into switching the American Autowire harness from the blue '70 to the red '79. Two lessons learned. 1) If you are happy with the wiring harness in the one vehicle, leave and buy another one! 2) Never, and I mean NEVER, put an aftermarket fuse panel where the OEM unit was mounted. There is just no room.

if you are talking about the driver side footwell location: it can be done - I made my own mounting bracket
 
if you are talking about the driver side footwell location: it can be done - I made my own mounting bracket
I found that the wires wouldn't reach properly if run from the stock location.
 
I found that the wires wouldn't reach properly if run from the stock location.

reach what ? - in my experience, the Painless wires are all extra long, so I didn't encounter any problems with that

yeah, getting your hands onto the wire trunk and routing of individual wires is quite tight with the fuse block on the left of the driver side footwell - but I guess stubbornness helps :hillbilly:
 
I made a simple bracket that bolts to the stock location and moves the AAW fuse panel forward an inch or so. I turned it upside down so the wires connecting to the fuse panel are forward and the fuses closer to the door. It allows for the bulk of the engine compartment wiring to pass through the stock grommet next to the brake booster. But getting your hand up in there to route wires over the top of the steering column is very tight. I guess I was spoiled with the location I used on the '70, which didn't come with a heater and put the fuse panel where the heater mounts.
 
View attachment 1040886 View attachment 1040887 View attachment 1040888 I just installed a universal "ez wire" wiring kit in my fj40, with great success.

1968 fj40.

Hazard light circuit tip:

In order for you to utilize the original hazard light switch you must do the following:


The universal wiring harness (ez wire, painless, or the like) runs power for hazard lights from fuse block through hazard flasher then to hazard switch.

This will not work.

You must modify the circuit.

Power must go from fuse block to hazard switch without going through flasher unit first.

From the back of new fuse panel cut the two wires on the back of hazard flasher unit. Leave enough on flasher side to re attach different wires from switch.

Attach the two wires together (this will send power to hazard switch without going through flasher.

Two new wires must be run from switch --back to flasher unit on fuse panel

Four new wires must be run from hazard switch to your lights that you want to operate when hazard switch is activated.

I spliced them in at the turn signal switch connection.

Here are some pictures. It worked!

View attachment 1040886View attachment 1040887View attachment 1040888
I know this is an old thread, and I am about commit a sin by suggesting it, but if I use an aftermarket hazard switch, does this whole problem go away? Just use a Painless etc kit and wire up?
 
I know this is an old thread, and I am about commit a sin by suggesting it, but if I use an aftermarket hazard switch, does this whole problem go away? Just use a Painless etc kit and wire up?
As long as you don't try to use the Toyota switch for appearance sake. The Painless/AAW kits are GM based and don't play well with Toyota. Something to do with sending power to a device vs power to a switch. I fried the seat belt/e-brake lights instantly.
 
I know this is an old thread, and I am about commit a sin by suggesting it, but if I use an aftermarket hazard switch, does this whole problem go away? Just use a Painless etc kit and wire up?
Hey @Vandal FJ which aftermarket switch did you end up using? I am installing a Kwikwire kit on a '73 FJ40, with a '78 (I think) hazard switch, so the wiring diagrams aren't exactly compatible. Almost ready to give up on making it work, because I'm not that worried about appearances TBH. And I don't feel like pulling the fuse block to bypass the flashers like littlebilly did in the pictures above, to be honest.
 
Hey @Vandal FJ which aftermarket switch did you end up using? I am installing a Kwikwire kit on a '73 FJ40, with a '78 (I think) hazard switch, so the wiring diagrams aren't exactly compatible. Almost ready to give up on making it work, because I'm not that worried about appearances TBH. And I don't feel like pulling the fuse block to bypass the flashers like littlebilly did in the pictures above, to be honest.
I have yet to actually get the wiring project done but I DID find in an old painless catalog the "wire around" for that hazard switch. I will see if I can find it and post it for you!
 

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