Get The LED Out

The 2016 Prius C comes factory with LED headlights, and as good as they are, well they aren’t quite enough.  The model 4 comes with fog lights, but it also comes with a lot of other things that I didn’t really need or want.  I knew from the time I picked it up that I was going to be adding the fog lights, I just wasn’t sure how the task was going to go.

I originally started by talking to Lithia Toyota about the cost of the factory parts.  The fog light housing, and bezels for them were around $500.  That didn’t even include the switch itself.  On top of that there was no guarantee that the wiring existed in the car.  So I waited.  A little while later I tried buying these off of Amazon:

There was a bit of an issue and for some reason they kept asking me to update the payment method.  The same payment method that I use for everything else.  Well I ended up grabbing a set off of ebay instead.  Either way it was the same basic kit.

The kit comes with the lamps, housings, switch, relay and the harness (not pictured).  Quality is well okay.  The paint on the housings is a bit sub par and has cracks in the crevices like it was wet when painted.  For right now I wasn’t going to worry about it.

I pulled the bumper cover to make the install easier, but you could probably do it with out the need to remove the cover.  Once you release 3 clips holding the stock block off plates in place you can pop it off and replace it with the new housing.  The lights hold on from the back using one tab and two screws.

If you plan to do this, I recommend doing it sooner than later.  The fog light housing covers much less of the front bumper cover than the block off plate. I’m sure after some time and miles the debris will build up behind the block offs and damage the paint behind them, leaving a less than ideal look when you do the swap.

The kit comes with regular halogen bulbs.  The factory headlights are LED, so I had to stick with the theme.  I ordered these bulbs from Amazon as an upgrade. From testing before the install they are quite a bit brighter than the halogens. Best of all they didn’t have a problem with my payment method!


With everything mounted it was time to wire it up.  The factory plugs for the fog lights were there and just taped up to the market light plugs, this was going to be easy!  I jumped on the Toyota TIS site and pulled some wiring diagrams.  The wire at the head light switch for the 4 wasn’t there.  Uh oh.  I move to the body module, and try to trigger it from there.  Maybe I just need to add an wire.  Nope! Out comes the module.

Then apart comes module.  It looks like we are missing a couple of relays. A couple of relays that I don’t have sitting around.  Okay maybe I can still use the factory plugs.  The output wire from the body module was missing as well.  And I gave up.  We are using the harness that came with the kit.

After a lot of debate I pulled the fender liner and added a grommet next to the release cable for the hood.


I attached the harness to the bottom of the bumper reinforcement. Then followed the factory harness up into the fender area.  The ground wire was a close to perfect fit for the factory ground point (red arrow).  The feed wire I zip tied to the release cable and followed its routing into the car.  I did end up cutting this wire to keep the grommet size and small as possible to avoid letting outside air or extra noise into the car.

I’ll have to update this with a couple of diagrams since I didn’t snap any pics inside.  I grabbed power at the inlet to the body module.  Power for the switch I piggy backed on the fused sized of the power feed wire.  The ground wire I needed to use for the trigger.  I piggy backed this on to the “tail light” wire out of the factory switch at the body module.  Now the fog lights can be used independent of the head lights, but still shut off with the lights completely off.  Much like the mods that people always want to do with their factory lights.

To finish off this round of lighting upgrades I replaced the license plate lights and front dome/map lights.  For these I used Phillips 6000K “peanut” LEDs.

I’ve tried other cheaper LED’s in the past on other projects and just couldn’t do that to myself again.  So far these have been great.  They are bright enough to light the ground behind the car (license plate location), and fill the inside with light  helping to overcome the cheapness of not having a center mounted dome light. I will certainly be ordering more of these.

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