15 - Light Frenzy 2

  Daytime Running Lights

Most recent cars have DRLs as standard equipment. This is partly in response to European Union Directive 2008/89/EC which requires all new model passenger cars and small delivery vans to have DRLs after February 2011. Partly in response to concerns over fuel efficiency and added cost, many car makers are using LED arrays as DRLs. I particularly like the Mercedes Benz designs. I knew I wanted my DRLs to appear as a “two rows of stars” as opposed to two indistinct blobs of light, so I also wanted to use LEDs for my DRLs.

Of course, if I was going to do that, I might as well add some other LEDs as the same time. So I decided to add LEDs to my fender vents, and LED underglow too.

 Types of LEDs

There are many different types of LEDs, this picture shows three of them. LEDs are commonly categorized by size, and when comparing these three types, the size is also a general indicator of their light output. The topmost is a type 0603 LED (least bright of the three) and the white strip is a type 3528 LED. The bottom two rows are type 5050 LEDs, which are actually 3 LEDs combined onto a single Surface Mounted Device (SMD). Note the three pairs of solder connections on each SMD. The circuit board of the bottom LED can be used with a combination Green/Red/Blue type 5050 LED which, when combined with the right controller, can display a wide variety of colors. Type 5050 LEDs are typically 3 times brighter than type 3528 LEDs, however they also cost more and draw more power. Prefabricated 12 volt LED strips like these typically have current dropping resistors built in, so they can readily be connected to your car.

  The Plan

Here is my circuit plan. I used a Single Pole Double Throw (SPDT) Center Off switch to control my DRLs. In the normal position shown, the DRLs turn on with the Ignition. When the parking lights are on, the SPDT relay is activated and power to the DRLs is provided by a Pulse Width Modulator (PWM) dimmer rated for 7 amps (97W, 13.8VDC) which allows reduction of the DRL brightness at night. The switch's alternate position allows me to activate the DRLs at anytime manually (even without the ignition). With the switch in the Center detent position the DRLs are off.

For the fender vent Lights I used a SPDT switch. In the normal position shown, the fender vent lights turn on with the parking lights. In the alternate position, the fender vent lights are off.

For the underglow lights I used a SPDT switch. In the normal position shown, the underglow lights fade on and off with the dome light. In the alternate position, the underglow lights are off.

  The Switches

Here is a picture of the new switches mounted on a fabricated bracket, along with the new wiring wrapped in black electrical tape, the PWM dimmer, and two 2 amp fuses. The blue and black boxes at the top of the picture are SPDT mechanical relays (the black relay was later replaced by the PNP transistor).

 I installed the new switches out of sight under my dash, mounting the bracket to the plastic around the OBD-II port. From left to right, the black switch is for the DRLs, followed by silver switches for the fender vent lights and underglow. The red switch is for Manual On. The copper “spider” next to the blue fuses is a homebrew heatsink fabricated from a copper pipe strap and bolted to the PNP transistor.

 I found the gray wire under the steering column (see picture at right) is powered when the key is turned to Ignition so I tapped off that wire to power my DRLs.

For constant +12v power I tapped off the electrical block behind the dash above the fuse panel.

  DRLs

 I planned to put a strip of LED lights on each of my front “cheek” intake vents because I wanted the DRLs to be easily distinguished from the headlights, with a "column of stars" look. I also wanted the DRLs to have a low profile. I bought a 50 centimeter 12 volt strip of 30 type 5050 white LEDs from eBay for $6.99 shipped. 12 volt LED strips can typically be cut into “modules” with each module having 3 LEDs. I cut the LED strip in order to fit 12 LEDs onto each front intake vent.

 Since I made my front “cheek” vents functional long ago (on my 13th day of ownership), I added plastic "bridge" strips between the grill bars to give the LED strips more mounting surface. 10 strips were needed for each vent. I used a combination of Krazy glue and craft glue (from a hot glue gun) on the backside to secure the strips to the vents. I drilled a small hole for the electrical wire in each vent.

 I cleaned the vents with rubbing alcohol prior to mounting the LEDs. Here are the vents with the LED strips wired and mounted.

 Prior to installation, I put a dab of silicon sealer on the solder connections.

  Fender Vent Lights

I bought a 12 volt strip of 12 type 3528 amber LEDs from eBay for $1.25 shipped. I cut the strip in half to give each vent 6 LEDs. I did not want amber light to leak out between the hood and fender, nor did not want to LEDs to be directly visible thru the vent, so I mounted the LED strips onto these deflectors that I fabricated from light gauge sheet metal.

 Here is the passenger side fender vent light (seen from the engine side) mounted above the vent and secured via double-sided foam adhesive tape. I used Molex connectors for quick disconnects. Amber light from the LEDs shines onto the subframe and is reflected/difused and seen thru the vents.

  Underglow

I bought a 12 volt 5 meter strip of type 3528 white LEDs with a density of 30 LEDs per meter from eBay for $9.70 shipped. Higher densities are available but I wanted keep the electrical load and light output moderate.

 I drilled a small hole in the inner fender liner and pulled the underglow wire thru. This is the passenger side.

 I was able to fit 48 LEDs on each side, here is a test of the passenger side. I cleaned the mounting surface under my running board with water first, then rubbing alcohol.

 Here is the LED strip mounted and the wire secured. I purposely mounted the LED strip such that it would be hidden, and to ensure I would get underglow and not underglare.

 I put a dab of silicon sealer on the solder connections.

 I removed my front fascia (I think this is the 9th or 10th time? *sigh*) in order to run wires for the DRLs and front underglow, and also to mount the front underglow LED strips.

 Here is the front underglow wired and ready to install. I used Molex connectors for quick disconnects. I cut small slots in the plastic front underpan to route the underglow wires.

 I was able to fit 6 LEDs on the sides and 27 LEDs in the front for a total of 39 underglow LEDs in the nose. This mount location protects the LEDs from most road damage (my front lip will scrape long before the LEDs).

I used the remaining 15 LEDs of my 5 meter LED strip (plus 6 white LEDs left over from prior projects) behind my rear bumper to provide rear underglow.

I put a dab of silicon sealer on all the solder connections.