Plug N Play Auto Headlights for the Prius C

This is a simple set of instructions for those who want automatic headlights on the C. Mine is a model 2 so that is what this is written for. Took me a while but I have mine working. Anyone can do this in an hour or less.

DEI 545T Nite-Lite This can be bought for 30 bux. Less on Amazon.

Unit has to be prepped to be specific for the C. I started by removing one of the 2 relays. I kept the one with large green and purple wires.
Second, I opened the module and cut the red wire. I did not want it to run my daytime running lights. I use the stalk for this feature.
Next, I removed the wires I did not need on the largest plug. I kept only the Red, Black, and Yellow.If you want automatic wipers, keep the green.
The light sensor needs to be stuck on the dash and run the wire down to behind the panel on left lower. This is where you will mount everything.
You will need to remove that panel and the lower one from the steering colum, 3 screws and a few push in connections along the edge. One screw is under the panel, below the steering wheel. The other two are on left and right side, behind wheel. You will need to rotate the wheel to get to them.
Wiring:
This is how I wired mine: I connected red and yellow together and hooked them behind the cigarette lighter, after removing the glove box. You will have 12 volts here with ignition on. You may want to tap a wire under the steering wheel.
I grounded the black wire, from module harness and the violet wire, from relay, to a bolt head behind the panel, in the dash.
The green wire from the relay has to be hooked to the headlight wire on the big connector under the steering wheel, on the left side. This unit throws a ground to this connection and turns on the headlights. Connector is L-47 pin 11. This is a light blue wire on the bottom row on the left edge. I would call it number one wire, on bottom, from the left. There are no wires on the top row of this connector. Will post a picture of this connector.
This will give you automatic headlights on the Prius C-2.

The sensor loses light, turns on the module, which throws the relay, and ground hits the wire on L-47 pin 11. I plan to cut one of the two sensor wires, install a switch, so I can turn this thing off. I may want to sit in the dark with the ignition on sometime and can do that with the sensor shut off.
Let me know if you need any more assistance. This is easy. I just had to figure out how the headlights worked and which wire went to ground when light switch was turned on.
Dan

 

The switch can be used to put in the sensor line but it is designed to plug in and override the driving lights, which I am not using.
The sensor will be mounted on the dash. Mine is at end of the pillar where the dash comes to butt. I can get a picture if you need it.
Yes, the high/low beams work normal.
Dan

 

Yes, there apparently is a difference in the newer units. This one you have to open it up, 4 screws, and cut the big red wire unless you want it to control your running lights. I keep mine on but I did cut the wire. From reading an earlier thread I find that the colors of wires are different on the relays. The provided switch, made to plug into unit, I plan to use to splice into the photo cell so I can shut the unit off. This is a simple install once you know where to connect the wires. In the photo, above, I left the needle sticking in the hole where the ground from relay hooks to that wire. Used the needle as a probe for my volt meter.
I am sorry this has dragged out so long. Only this week did I get my light sensor back. Should I order another unit it may be from Amazon, where I see them for 19.95 and up, plus shipping. This feature is just something I got used to on previous vehicles and did not like having to turn on my lights with the switch. Not a big deal to most folks, I am sure.
Headed out to tidy things up now.
Dan

 

66. Its my daily driver. Painted to match our GMC coach. We tow it a lot.
Dan

 

Notice in the dash picture where I mounted the light sensor. I found out that if you gently push the base of the post cover in, you can slip the sensor wire down in the crack out of site. Looks like a factory set up now.
Dan

 

Well, when I took the photo I did not have it hidden yet so I thought I needed to mention it. It will be hidden all the way. Goes behind the rubber gasket in the door down to the bottom of dash.
The unit is quick to turn on the lights. Id say 3 seconds after key is turned on the relay throws the ground to the pin. Of course, it goes off immediatly when the key is turned off.
Dan