Need help w/ 72 fj40 hazards switch wiring

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Jun 21, 2012
Can someone plz help me figure out how to wire my push/pull hazards switch and wipers? I'm using the painless wiring harness I've wired everything but wipers and hazard switches. Im use the 10107 fj40 painless manual and haynes book but the painless manual doesn't have how to wire a hazard switch for a fj40 72 only for a pre-72 witch is very different. Plz help???
if you still have that section of your old wiring harness that would be helpful, since you need to recreate some sections that Painless doesn't tell you about
Yea I still have it but I can't figure how to wire it up can't he manual tells me have to create different circuit and make 3 in. Jumper wire but from where to where that what don't get
get the Toyota wiring diagram for your year - it shows what was originally in the truck - once you have figured out where the Painless wires go (and don't), recreate exactly those connections

no matter how long you try, you won't get anywhere without the correct OEM wiring diagram for your year truck - unless you use different switches

BTW, search for Coolerman here on MUD, in his sigline is a link to wiring diagrams, including '72

on the wiper, do you still have the channel wiring in the windshield ? if so, use that and lay a new ground
Forget the painless piece. You have to recreate some things based on original diagram. Understand the old first. I have a 71 with one flasher and I believe the hazard switch was 9 wires. Const hot, switched hot, power to flasher, flashing voltage back from flasher, flashing voltage to turn switch, and 4 wires to the lights at the corners... Is that 9?

Other stock configurations had 2 flashers: a separate one for hazards and turns and I think that hazard switch only had 6 wires.

You have to know what you have first. If its 1 flasher with integrated lights for hazards and turns like mine then I can walk thru it from memory. If two flasher set up we need to study old wiring diagram.

You can source hot wires from the new harness and prob the wires that go out to the corner lights. Other inter-connects sometimes need to be added.
Heading to the airport but I'll be back on tonight from hotel. See what you have and we'll walk thru it.
Ok. 3 hour delay...

Here's how it works with one flasher. The hazard switch, like all of your other mechanical switches just routes voltage internal to the switch from wire to another (or multiple wires).

With only one flasher it needs to handle both hazards and turn signals, which is why there are 2 sources to the hazard switch. The constant hot will be used so hazards can be used with no key. The switched hot is used for the turns to only operate with the key.

One of these sources, depending on switch position, is routed from the input wire to the wire that goes out to the flasher. The output of the flasher comes back into the switch on another wire (now we've accounted for 4 of 9 wires). If the hazard switch is in the ON position, the flashing voltage goes out of the hazard switch on 4 wires to the front and rear lights so they all flash. Now we've accounted for 8 wires.

If the hazard switch is OFF, the flashing voltage from the flasher is NOT routed to the lights, but it goes out on the 9th wire to the turn signal switch.

Now it is the INPUT voltage that is already flashing to the turn switch. That switch then routes the voltage to left lights or right lights depending on switch position.

The brake switch is wired into the turn signal switch so that it can override and illuminate the rear brake lights no matter what other flashing situation you are in. Brakes have precedence.

It's actually a pretty clever set up.

Mine is factory with one flasher.

If you have two, we just need to understand your original wiring diagram.

Hope this helps.
Thank u guys I figured it out. The old hardness switch has 9 wires two GB two GY one of each go to brake switch and the others to signal indicator. The GL or more like Green Blue is connected to the painless brown wire 952 I believe is the wire number the rest of the 4 wire must get canceled. Thanks to all of u the last thing now is my wipers

Users who are viewing this thread

Top Bottom