Footwell Lighting tied to Dome Light how-to

Success! I installed led footwell lights. I wanted the footwell lights to work in conjunction with the dome lights. From searching around the forum I knew the negative (-) dome light was a blue wire accessible from the driver’s a-pillar, but I didn’t want to run a wire down the a-pillar. I found out (from a Scion forum) that the blue negative dome light wire is Pin #52 in the white 56-pin connector on the back side of the driver’s dash fuse box. It’s the lower plug on the back.
I am not going to include the details on how to remove dash panels or how to connect the wires to your lights. These instructions are readily available.
If you are going to do this don’t forget to remove the dome light fuse in the engine compartment fuse box. The last thing you want to do is fry the $400 Door Lock Relay which also controls the dome lights.
I used a telescoping mirror, a head-gear flashlight and a pick tool to separate the wire from the rest of the harness. Putting the t-tap on this wire with such limited space is no picnic, but I managed to put it on.


I tapped the +12v wire as illustrated in the Illumination door sill instructions. This is a constant +12v. It’s a white with red markings wire, Pin #24, behind the driver’s foot cowl.
Note: Disregard the Pin #12 (yellow) in the diagram below. That is used for the door sill lights.



Here is how I tapped the +12v wire. I also added an in-line 5amp fuse after I tapped this +12v wire.

I used blue 18-16Ga t-taps and 20Ga speaker wire. I routed the speaker wire along the emergency brake cable making sure to stay away from any moving parts. I used small butt-connectors from Radio Shack, part #6403073 for the small wires.
The rest is pretty straight forward. I mounted these 12” flexible led strips. They mount with the adhesive tape on the back of the strips. For the driver’s side I cut off 6 of the led’s from one of the strips so it would fit on the flat edge on the lower dash panel. For the passenger side I cut off 3 led’s.



This is the end result. The led lights turn on with the dome lights, when any of the doors are opened including the hatch door.

 

Yes. The led lights fade with the dome lights.

 

I had to go check this. To answer your specific question...Yes.

With the dome light switch in any of the 3 positions, the led lights turn on/off when a door us opened/closed or whenever the car is locked/unlocked with the remote or the SRS. Meaning if you unlock the car, the led lights will turn on. If you don't open the doors the led lights will simply fade out after 30 seconds. If you then open a door, the led lights will come back on.

The footwell lights behave the same way in any of the 3 positions on the dome switch (Off-Doors-On). Turning ON the dome lights does not turn on the footwell lights.

This is something I was completely unaware of...

When you START the car, the led lights will fade off if they are still on (closed doors, 30sec delay), again regardless of the dome light switch position. When you turn the car OFF, the led lights turn ON. If you sit in the car after turning the car off and not open a door the LED lights will fade off (30sec delay). The lights will turn on when you open a door. This is the same behavior for the dome light if the switch is in the middle position.

The footwell lights are controlled by the unlocking/locking of the car, opening/closing of a door, starting and turning off the car. With a 30sec delay each time the lights are turned on. With the overriding behavior by any open door. If a door is open the footwell lights stay on.

So, I'm pretty sure the switch on the dome lights do not control the negative (-) blue wire. Which I think is a good thing. I specially did not want the LEDs to turn on when the dome lights are turned on with the switch. I think it would be distracting to have the blue LED lights on when I'm trying to use the map lights. However, it might be nice if the footwell lights did NOT turn on whenever the dome light switch was in the OFF position.

Picture of the passenger side mounting location

 

Yes, the +12v wire I am referring to is behind the driver's left foot panel, near the foot break. It has a "plastic nut" holding it in place near the foot rest and 2 push-pins near the door frame. You just have to pull on it pretty good. The driver’s side fuse box is locate under the dash right above the foot parking break pedal. If you look straight up on the foot break, you'll see the small fuse box lid. The 56-pin connector comes into the back of that fuse box. Use a mirror and you'll see the wire bundles.

As far as the wire harness on your 2013 Prius model II being the same as mine, I cannot be certain. I have a 2012 model II, so I would imagine they're going to be pretty darn close if not exactly the same, considering I found the wire in a Scion forum! Let me know if you need more clarification.

 

Yes, that's the wire.

And that's correct the footwell lights do not turn on when you turn on either of the map lights or when you turn on the switch on the overhead console to turn on the lights.

If you want to verify you have the correct wire, do what I did, before splicing into the wire. I used a single wire crimped to a tiny molex pin connector (or dupont connector) that I inserted into that pin #52. That way I was able to test the lights. You can buy those molex connector from Radio Shack.

Something like this...