Fog Lights: Install [Retrofit] fog lights on 2010 Prius?

Nothing!

 

I can only speak for my self. I am obsessed with OEM/factory/stock look. If I do any sort of modification I want it to apear as if it came from the factory that way. Dash mounted OEM look a like switch that I am going to use is the minimum I would do. Prius came with stalk switch but some Toyota model came with a dash mounted switch so it's acceptable to me. If the stalk switch was cheaper I would go with that. I think I am going to spend $100 toward another modification.

 

I like your attitude.

By the way, the stalk switch document you created, including the 12 photos, was excellent. So well written that anyone can follow it.

 

I did this but connected the trigger for relay to my low beams so they do turn off when the lights time out. I can't of course turn them on w/o the lights on. BTW, I'm pretty sure you are running 12v to your dash but a much lower current then w/o a relay. I used the switch from the 3rd Yaris kit I bought and it looks factory.

 

Now that i've got the switch in place, i will be running the wire this weekend to the lights. I bought a small spool of 14 guage wire. Should be plenty to handle the 110 watts for both lights. I will run it from the ecu or relay through the firewall at the point just above the accelerator. I think it will go smoothly.

I am still undecided on where to make the connection point. I do not want to remove the main body ecu as it is a hassle. And I don't even know what I'll see when I get in there. I like the idea of conencting up that missing pin. If I do it that way, I'd have the choice of buying a pin or borrowwing it from the unused conector.

If it is truly unused, I'll probably just use it as I do not want to have to wait for another part to arrive. I'll just solder the new 14 guage wire right to it and pop it in. From there, i see what appears to be a good routing point for the wire.

If it appears that that wire is used (and is actually connected to ground) I probably won't use it and will have to figure soemthing else out. At this point, I'd like to be done with the project so I can give full attention to my other mods (and wrap them up as well)

 

Finally. I finished the install. Everything works great.

It was a good install. There was a great route for the wire from the cabin to the engine compartment. I went through the firewall in the same place Toyota did (very easy there). I do have to say that the easiest part was installing the OEM headlight stalk. It was faster than installing the fog lights and wiring, and did not require me to spend half the morning all twiseted and on my back.

I'd put the dissassembly at about 25 to 30 minutes. The fog light install at about 20 minutes each, and the wiring at about 2 hours (mostly due to the cable ties, electrical tape, and just tucking everything away neatly). Reassembly was about 20 minutes. All in all, it was about 3.5 hours (not including the headlight stalk switch).

Pictures and description to follow soon.

It feels good to scratch this of the list.

 

Hawkmoon, great job on the fog light install! Looking forward to reading your "how-to". Your other ones have given me so much confidence, I had no problem taking apart the Prius to install HIDs and my fog lights (just wired mine to come on with my headlights.)

 

The usual disclaimer applies. I am posting a detailed history of what I did. I am not providing any kind of advice. Before undertaking anything similar, please do your own research and diligence. The following is how I added the fog lights. My explanations follow the order of the pictures. The pictures detail the passenger side, but it is the same for both, except where noted. I allowed about 20 to 30 minutes for each side.


1. I placed a jack behind the wheel at the location indicated in the manual. I raised it a bit, not enough to raise the wheel off the ground, but it gave me about another 6 to 8 inches of clearance under the bumper. The picture shows the black flashing. I removed the 4 screws. When the three black screws are removed, a little piece of plastic can be removed. I then removed the 4th, silver screw. There are two clips. A small flathead screwdriver can remove them well. I inserted it under the round center part, but over the rim (where the rim cut-outs are) and gave the crewdriver a little turn. The round center disc will NOT pop up unless the rim is pressed tightly against the car. Trying to pop up the center piece while allowing the rim to come with it will cause a lot of trouble. I popped the center disc up a little bit, and the whole snap comes out very gracefully. These snaps do not in any way require muscle or prying so long as the center disc gets popped up while the rim stays flush against the car. Once all is removed, I popped the flashing out from the front of the car. It does not come off entirely as there are two rivets in the back. Freeing the front of it from the bumper and lowering it a bit toward the floor gave plenty of access.


2. I removed the nut (this picture shows the nut already removed). I then unclipped each of the 4 clips, (while pulling the gray cover toward the wheels very slightly). I unclipped them in the order listed (from A to D) I could not see “C” from under the car, but it can be done by touch alone. Once the clips were released, the assembly can be pulled toward the wheel. Then, from the front of the car, I was able to unclip the wire harness. The clips are on the reverse side of what is pictured. I just reached through the hole where the cover was, and was able to depress the two clips by hand and pop it out. Note that the driver’s side as two more clips holding the wire harness in. I was able to remove those from under the car.


3. The Lights fit into the cover, and only one screw holds them in. None of the parts came with this screw, but any course-threaded (as opposed to fine machine threaded) screw should work. I just had to be careful not to use a screw to big in diameter, as it would crack the plastic. Also, a flat head (as opposed to a fluted head) screw is used. There is no need to over-tighten this, it is just plastic. Also, I had to make sure that the plastic of light fixture was seated properly in the cover where the screw hole is. Note that when everything is put together, you will see a small gap between the front glass and the plastic housing. The plastic housing does not actually touch the glass.

For the installation:

First, the light assembly was positioned over the screw (where I removed the nut) shown in picture 2. The whole assembly was then brought straight forward. While looking at it from the front, I was able to reach a hand underneath and push it forward while visually seeing that the four clips were lined up. When everything was lined up, it snapped in place. I was careful to make sure that ALL clips engage. They do not all make a satisfying clipping sound, so I was careful to make sure each engaged properly. I then replaced the nut on the screw (being careful not to overtighten it). Then I clipped the wire harness back in.

I did no more reassembly. My next step was to do the other side of the car. This was so that I could properly run the wires from the passenger side to the driver’s side. I will include that explaination in another post on how all this got wired up.

 

Before I describe the procedures I followed for wiring, I wanted to point out the two different ways I considered wiring this up.

1. As described in the first picture, this uses the OEM headlight stalk switch. All of the wiring is present to the ECU. Thus, the wiring is somewhat simplified becasue it uses the stock fog circuit, which includes a relay and fuse. The only wire to run is the 12V+ line from the ECU to the fog light. There is a groundpoint by the fog light that also needs to get connected. I used 14 guage wire from the ecu to the drivers fog, and then 16 guage wire from the driver's fog to the passenger fog. I used 16 guage wire for the ground since it was a much shorter run.

2. Any other install that uses a switch (and not the OEM fog headlight stalk), which I had considered for awhile, I would have done this way, as described in the 2nd picture. Note that the switch switches ground to the relay, meaning there is less chance of getting a short. A relay and fuse is required in the engine compartment. For the fuse, I would have used the same amp rating as what was stock. (15 or 20 i think, I can't remember). I would probably have used 16 guage wire for everything under the hood, except for the green wire running from the switch, through the firewall, and to the relay coil. I would have gone thinner than 16 guage for that. Maybe 18 or 20.

Please understand that this is my best GUESS as to the wire gauges, and not a recommendation in any way. If anyone wants to recommend something else to me, please let me know.

I'll post the install info later.

 

As usual, fantastic write-up. Thanks, hawkmoon!

This gauge is just fine (and then some, in the case of the 14 ga - but that's good, it will ensure there's very little voltage drop at the lights).

Again, these gauges are fine. You could easily use 20ga for the green relay coil wire.

Did you end up scavenging a pin from the L8 connector for the +12V? Anxious to hear where you went through the firewall.

Finished my auto headlights using the factory ECU on Saturday (will write up later) - on to fogs Sunday.

 

Re: The kit is here!!!!!

Put the switch in yesterday, works well and looks stock. For anyone that used this switch does the fog light icon light up when the fogs are off?

 

I think everyone has done a great job on all the post here. But I have a question? Could you splice into the running lights and or the headlights circuit wiring, so when they came on so did the new fog lights? So there would be no need to add a switch.

 

Exactly. I figured 16 would be fine, but I wanted to reduce the voltage drop considering how long the run was.

I did scavenge the pin because I ran out of patience. There was no realistic way of getting to the relay without removing the ECU, and that is not easy to do. If I bought the pin, it'd be so simple. Just pop it in, and move on to the next step.

Great! Look forward to seeing it.

 

Yes, but you need a relay.

 

Yes, you can do this. I'm going to reference you to Hawkmoon's HID install post here. Get a relay, and wire it as so:

Terminal 87 - Connect to the +12v source under the 10mm bolt in the fusebox that Hawkmoon shows in the post.
Terminal 30 - This is the +12v you wire to the foglights
Terminal 85 - This is the ground, which you ground in the same place Hawkmoon grounded his HID relay, which is a 10mm bolt on the frame of the car by the hood
Terminal 86 - This is the turn-on for the relay, you just get a quick snap wire splicer and tap into the headlight wiring right behind the headlight.

It's that simple - if this looks complicated, it isn't. You literally run one wire to the fusebox, one wire to the vehicle frame, one wire to the fog lights positive lead, and the last wire to a splice on the headlight wiring.

This logic is this: when the headlights turn on, it allows the turn-on lead to close the relay and now current can flow from the vehicle to the fog lights. Thus, the fog lights are on anytime the headlights are on. This makes the fog lights turn off automatically when the headlights turn off too.

I did this install, and it works perfectly. Very simple. Now I just need to find some decent fog light bulbs that look nice with my 4300K HIDs.

 

I am not sure I understand it but thanks for the follow up!:juggle:

 

I did it!

Well, it took way longer than I thought. I used Yaris wiring kit but had to modify the wire lengh in few placess to fit into Prius. I tapped into main beam +12v signal in the engine bay to supply the signal to the relay included in the wiring. The main +12v plug plugs directly in to the fuse box. The connector supplied in the kit was a direct fit. Feeding the wire through the firewall wasn't easy. It took a while but I found a hole specifically designed for this operation.

Btw, the OEM look alike switch is not illuminated in matching green. Damn... it's orange!
I guess I will open up the switch and see if I can change the color...

anyway I will post some pictures tonight.

 

Congratulations! Looking forward to those photos - any details of crossing the firewall?

 

I used a nipple to the passenger side of a wire bundle plug. The wire bundle plug is just above and between the brake and gas peddle. Virtually impossible to get thorugh from under the hood but pretty easy to get to from under the dash. Take off two screws and can then move the panel that has the foot lighting LED. My switch is illuminated, orange, when the lights are on but the fog icon isn't illuminated when the lights are off.