Plug N Play Auto Headlights for the Prius C

Did you take detailed pictures of each step ? I'm all thumbs and would love to have auto headlights on the car... the writeup sounds a little intimidating for me

 

Thanks for the reply Dan this is great. If I want the lights to go on with the wipers where does that little green wire hook up?possibly with the yellow and red?

 

Worked fantastic Dan thanks for the detailed instructions.

 

Sorry to be so dense, Dan, but a couple of questions. You say to use only the relay that has the large green and violet wires. What do you do with the red wire connecting the two relays? What about the small blue wire (from the other relay) that joins, at the plug, the red and green wires from the relay you keep?
Thanks.

 

big Jake you just cut those to seperate them. Also don't forget to open the module and cut the red wire inside there otherwise the lights will be on at all times when the car is on instead of turning on automatically when it gets dark.

 

Thanks for the quick response. I'm a bit leery of all this, given how poorly I understand it. I just miss the automatic headlights my old Corolla had!

 

This is the bees knees when it is done.If you have any direct questions feel free to drop back here or inbox me and I'd be happy to walk you through whatever part you are leary of. Don't be too scared, I did the backup camera install first and it was wayyyyy harder than this one.

 

Great directions. Just did this mod over the weekend. Originally wanted to connect the wipers also. After looking into it I realized it would flash lights when using mist or intermittent because the ground signal is the steering comlumn only when the wipers are told to move.

The only issue I had was I couldn't get it to work and was getting power to both sides of the photocell connection and to the green wire (instead of the proper ground). Called the tech line, but they are closed on Sundays. Took a break and went back to look at it and realized I never connected the black wire to ground. Connected it and it worked as advertised. Rookie mistake. Glad the tech line was closed.

Next I'm upgrading rear view mirror to auto dimming with garage door openers, driving lights, and back up camera. Will be upgrading stereo speakers and adding an amp and 8" sub over the winter.

 

so how do you remove the glove box and how do you "connect" the wires to the cigarette lighter 12V? i'm not very good with this stuff. thanks

 

For the C. Open the glove box and remove contents. Pull the rod connection on the right side, it just pops off and on. Press in on either the left or right side of the gove box to free the tabs that act as stops, the sides will flex in enough. When it is pressed in enough you can open the glove box more, past the stop. Then do stop on other side of glove box. After the side stops are free, just pull the glove box toward seat it will pop off.

The cigarette lighter is just inside on the left side. The connection has a clip holding it on, mine was faced away from the glove box. Check which wire provides switched 12v power, mine was the gray one. I stripped away some insulation, soldered the yellow and red wire on, and sealed the connection. You can also just buy a wire tap and use that, it is a lot easier way to go.

Reinstallation of the glove box is just the reverse of the removal. Pop it on the bottom, press side stops in, push rod on, fill it back up, and close it.

 

Unsuccessful attempt to install following these instructions this afternoon. Here is what I did:
* Cut the red wire connecting the two relays and cap wire with shrink tube
* Opened the module and cut the red wire
* Soldered yellow and red wires from main harness to switch 12v at cigarette lighter
* Grounded the purple wire from relay and black wire from harness
* Soldered green wire from relay to first blue wire in the stem control harness.
* confirmed the photocell was going to ground when I covered the sensor with my fingers
* Plugged the photocell into the module

I powered on the car, but when I cover the sensor, the headlights do not come on, Everything still works from the stem though. It was getting dark and starting to rain, so I had to wrap up for the evening.

Anything glaring wrong above? Any advice on trouble shooting this? I will confirm I am receiving power at the module from the solder connection at the cigarette lighter, but not sure where to go after that.

 

NEVER CUT THE RED WIRE!!!! That's how bombs explode!!!! ... ... ... .... sry... couldn't help myself... Hopefully someone will offer actual advice.

 

UPDATE: Finally got around to investigating this again. Turns out I tap into the striped power wire on the cigarette lighter. I move the yellow and red wires to the solid gray wire, and everything works as advertised.

 

Added the auto headlight override switch today.

 

I'm probably missing something, but my Prius has headlight settings for off, on and automatic. I believe the delay can also be programmed.

 

What you're missing is that this is a Prius C forum, and the C doesn't have auto headlights.