Toyota Corolla DIY

The DRL lights are not controlled by a step down in positive voltage, as one would think, but instead controlled by what appears to be pulsation of the ground in the circuit. With halogens this is not an issue, but with DRL’s the problem becomes exposed due to the voltage step up.

Here is what I did to disable the ecu’s ability to control the ground signal … I added a ground to the wiring, haha! As simple as this seems, it worked. I read on here that some were using capacitors and they were exploding or something? You only have to add a ground to one headlight (I chose the passenger side as there is more room) and it stablizes the ground for both headlights. In doing this, my DRL’s still function as usual, they are just brighter. All of my other lights function as normal, and the daytime/nighttime sensor is also still functioning as normal. I have pictures, just to show what I’m talking about. I will (and would strongly recommend doing this) solder and heat shrink the added ground wire to the existing DRL harness.

In my opinion Dave, since you are having your own kits made, you could add the extra 8 inches of wire and terminal ring connector, as part of the kit? What do you think Dave?

Step 1 (the way the wire comes from DX)

Step 2 (the modification to the wire)

Step 3 (where I grounded it)