Hazard lights won’t turn off

Sticking hazard button? Wouldn’t hurt to disconnect neg lead from battery before investigating. That’d stop the battery drain too, for the interim.

 

There's a kind of a known issue where the hazards blink in a way that kind of depends on the speed of the car. I think I know how that might be caused. Is that what you've got, or are yours just plain stuck on, flashing at the normal rate?

What happens if you unplug the hazard switch? Do they stay on still?

 

# 10 wrench....the battery is in the trunk.. passenger side

 

I think Tim means a 10mm wrench, which you can use to undo one of the battery clamp posts in the back of the car.

If that's something you'd do, you might also consider just unplugging the big white single cable in the underhood fuse box. Easier to get to and no wrench involved. Either way, you'd still have to reset your radio stations, clock, auto-up windows, etc. when you reconnect.

Referring back to #3, got any more details on the exact way the hazards are behaving? There are some related cases here on PriusChat.

 

BUMMER!!!!! Guess u could use hand signals.

 

Seen this on another site......
I had a Prius in the dealership today with the hazard lights flashing all the time and the rate at which they flash increases with speed. I also noticed a left rear speed sensor code stored in the abs ecu even though the abs light was not illuminated and I had an active speed sensor signal. The only common connections I could find between the hazard lights/turn signals and vehicle speed is the abs actuator. Using a long hook tool I unplugged the abs actuators electrical connection (without removing the wiper cowl) and the hazards stopped flashing immediately. (Note, doing this will set codes you may not be able to clear) An internal short circuit inside the actuator is the problem with this vehicle. FYI, depending on year and mileage, Toyota has enhanced coverage for the abs actuator on a Prius.

 

and anther one...

Xiao answered 11 months ago

I had this problem and engineered a fix. The issue seemed to be a short on the harness. My solution involved disconnecting the existing wiring from the flasher relay and jumping a wire from the hazard switch to the relay. The fix is documented in the following thread. Page Not Found | PriusChat crazy.201911/page-2

 

Around here, no signals, you’d blend right in.

 

From another post
finally got time to work on prius abs actuator was shorting into hazard lights, replaced the acuator with a used one got for 100 bucks two hours of labor and a hard brake bleed and the old car is back up and running thanks for all your advice

 

Right, the hazards-blinking-faster-with-road-speed issue has been an oddly common one discussed around here before, which is kind of laugh-out-loud in how specific it is; there's really only one way to see that happening. One of the jobs of the brake ECU is to generate a "speed pulse" output (SP1) that goes faster with car speed. The speedometer doesn't use it (just gets the speed over CAN), but other common accessories do, like the NAV for deciding when you're moving too fast to push buttons, or the radio for bumping the volume at higher speeds, and so on.

There's also a HZRI wire that connects the hazard switch to the brake ECU (I'm not sure why, but I guess so the ECU can know if you've turned the hazards on. In Techstream you can see it as an input.)

It turns out the SP1 and HZRI wires are right next to each other in the connector to the brake ECU under the hood, as discussed more in this thread.



If that problem ever happened to me, I think I would do a quick look for corrosion or tin whiskers right near those two pins, before I would jump to any more drastic conclusions about failure of the $$$$ actuator. (I might also think about just sticking a diode in HZRI. If it's just meant as an input to the ECU, then it doesn't need to be able to trigger the hazards from there.)

That might none of it be on point for the OP though, since this is a different situation where the hazards are stuck on at a fixed blink rate. So they're not being bridged to SP1 in this case. There could still be something just bridging that circuit to ground though. Worth a look.

Well,if you currently hear clicking but don't see light, it's more likely they disconnected something downstream of the flasher (or pulled a fuse maybe, though I haven't checked the diagram just now for what fuse that would be). If the problem were the switch and they unplugged it, the clicking would stop.

I'm not familiar with exactly where the switch is in a v or just how the v's panels pop out, but it's usually pretty simple.