How to Auto-on Headlight installation

Ok, I have to think the relay wires have changed colors, as noted above. One has 2 blues and a brown. This must be the one that we discard, cut red wire that hooks the two together. Now, the small blue wire, from the unused relay, goes to the module 3 wire plug. Cut the blue wire from the plug?
This might be a simple mod for lots of us, but we need a step by step. The write up is pretty good up until certain points. I think the author is very familiar and assumes we are too. There needs to be a little more information added here, especially if the colors of the relay wires have changed. I almost discarded the wrong relay. All of the colors on the 7 wire plug, into the main module, are same as in the write up. I have not yet looked at instructions that came with the module. Nor have I dismantled the dash. Just trying to cut the wires and relay that I don't need. I am hoping someone that has done this mod will check in here or maybe even the original author. It is an old thread..
Will keep working here to figure things out. This is going to be a great addition to our C. I hate having to turn on the lights.
Dan

 

Still in the house getting things ready. I keep seeing "I connected the black wire and one of the relay lines". What does the "relay line" mean? I have no extra wires from the relay. Got the purple with fuse. Got a big green. Then only a small red and green that plug into the module. There is no other "relay line". If I can get this defined I think once I get into the dash I can hook this up. Need an ignition "hot", ground, then figure out where the fused purple and the large green attach. May be obvious when I drop the lower dash.
As I said before, I am glad I found this old thread.
Dan

 

Saturday, 4-20-13. I seem to be stuck as to where the 12 volts, purple, and the green from relay are hooked. I found a hot that is keyed so I have the yellow and red to that. Got foto sensor installed. Found a good ground for black wire. Lyining in the front seat now with laptop. About to quit for now til I get the light switch figured out.
Dan

 

Ok, buttoned it all back up and gave up for today. Will do more research. The thread on the Prius site turned into a Canadian Stalk thread. I still read most of it last night. I grounded the black wire. Hooked red and yellow to a "keyed on" pin under the steering wheel. Used a voltmeter to find it. Might move it to the wire that runs to the cigar lighter as the author of the post did. I have sensor mounted. I am right to the green and violet from the relay. The violet has the fuse. Green has nothing. These two are the larger, prob # 14 gauge wires from relay. When I get this thing working I will try to do a write up on how I got mine to work and make it simple. " Connect this wire here, connect this wire there" etc. I cut the wiper wire off as I don't care about that feature.
Now, mine has a red looped wire inside the module. This is so the headlites only will run when key is on. Makes no sense to me. If not wanted instructions say cut it, which I will do. The C has that feature on the stalk "DL". Also, remember, the new module has different color wires than the one the author wrote about, from the relays only. All other wires are same colors.
This is going to be a very needed mod for me. Can't wait to get time to figure out the light switch so I can get the two remaining wires installed. One does not need to be a radio operator to do this. Once the connections are noted anyone can do it.
After reading from above for the 47th time I am thinking the fused wire from relay goes to power and the green one to pin 19.
I will be back.
Dan

 

Today I got one more wire hooked up. Either of the big wires, green or violet will trigger the relay. But, the violet has the fuse so I hooked it behind the cigar lighter. Now, when key is on the relay is triggered. One wire left to hook up. It is the green one from the relay that has to go to headlight wire. Don't have any more time until Saturday to fool with it so everything is buttoned up behind dash for now. This will be a simple install when I get this last wire hooked up and write this in a 1,2,3 instruction sheet. I think I have the headlight wire located but will double check it with voltmeter this weekend. So glad this thread popped up. Maybe I am the only one interested, ha.
Dan

 

Good luck.

It takes courage to be a guinea pig. Especially electrical related.

 

I want the auto headlight feature in my c. Had it in an escalade and my bmw and its hard to go back to manual. Spoiled I guess. If it works I will buy the unit and have it installed in my 2013 c. Just had them put in the back up cam and its really nice.

 

Looking forward to your instruction sheet I really miss auto-on headlights !

 

Well, I did not have much luck today. I keep reading over and over that the guy who started this thread for the C grounded the relay and then attached the other wire to pin 19 of the headlight switch. Twice today I have had the cover off the lower steering wheel trying to determine just what is going on with the 10 pins on that switch. Mine is a 2 and his was a 4. His switch had 12 pins in use. So far I have had no luck. I did throw 12 volts onto one of the pins and it got hot. So far I can see that I damaged anything. Now, my next adventure with the voltmeter will be to see if the headlight switch is throwing pin 19 to ground. If it is, then I need to rewire the relay from 12 volts to ground and throw the ground to pin 19. I suspect this is what is happening but I am tired of messing with it today. Also sent a private message to the author of this thread. When I get this figured out I will post and start a new thread with simple instructions.
Dan

 

Could not wait, back at it. Pin 20 on the headlight switch goes to ground when headlights are turned on. So, I rewired the relay to switch ground to pin 20. Turn key on, headlights come on, but it is daylight. For some reason the sensor is not working. Will contact the company.
I went back to the original Prius thread and found where the guy was switching the ground. Then I took my ohm meter and found that indeed pin 20 goes to ground. My car is a C-2. Pin 19 does not work on the model 2. The original poster here had a c-4 and has more wires on his headlight switch.
So, I am hoping to hear back to see what I might have not hooked up correctly to cause the sensor to not operate the system. I will return.
Dan

 

Sending engineering vibes your way Dan!!!! Go Dan Go!Go Dan Go!

 

I need all the vibes I can get.
Thanks

 

Well, I worked on it in the dark tonight. Wanted to make sure it would not work. It didn't. Waiting to hear from the place I bought the kit. Acts like the sensor is not turning on the unit so it can throw the ground to pin 20. Pretty disappointing after finally figuring out how to hook everything up. Will let you know what I find out. Hope they will replace it. If not, I will find a different dealer to buy another one from. 30 bux is a bargain if I can get one to work.
Don't give up on me yet.
Dan

 

Got an email to send the unit back. Guess it will now take a while before I can finish this up. I am tempted to just buy another one for 30 bux, but I won't. Will post when I get it back and installed. Instructions for the C will be 1-2-3 easy.
Dan

 

Just got word from Sonicelectronics that they are sending me a new unit. Seems I got a dud. Car is wired so it should be plug n play when I get it back. I will write up a "how to" for the C when I get it back and its working. Will be a simple hook up for the C. I have found the wires needed with the volt meter and by reading prior posts. This should be simple for anyone that wants automatic headlights. 30 bux shipped.
Thanks for hanging with me.
Dan

 

I do miss this from my Volvo. Will watch for your update. Thanks, Dan!

 

I was glad that they did not make me strip the harness from the car. I sent the module and the sensor only. They are very good at communicating with me. I got mine from Sonic Electronix. For 30 bux, I am thinking about ordering another one for my motor home. I find them cheaper on Amazon but the service from this store is worth the few extra dollars.
Dan

 

Dang it. 3 weeks and I get the main unit back, no sensor. I was so ticked I called them up and they are sending me one right out, or so they say. I sent more than one email asking them not to forget to put it back in before returning the new main unit.
Oh well, just wanted yall to know I am still here waiting. When I get it, and everything works, I will have a simple write up.
Dan

 

This has turned into a real fiasco, trying to get my light sensor back from Sonic Electronics. After not receiving it today I contacted them and found out they failed to ship it as promised 9 days ago. I really can't recommend buying from them now. Check Amazon. I have seen new units for as low as 22 bux. I should have just ordered another complete unit. Would be finished by now and have the write up done. I have just about forgotten most of what I did to locate the wires now. Oh well, maybe next week. The harness is in place so just need the sensor to plug into the main unit. Should work.
Thanks for your patience. Mine ran out today.
Dan

 

Gotta love that! Thanks for the update, Dan.