DRL Kit Install for US MDX

I bought the PilotLighting DRL6 kit from Styling Concepts for $55 (special order only), which is for 9006 lamps and presumably plug and play according to the manufacturer. To be honest, if it were returnable (which special orders are not) I would have sent it back, abandoning my DRL quest altogether (other kits are available, but all of them require a fair amount of cutting and splicing). Now that it's in and operational, I'm glad I have it...but the lack of an easy plug-and-play installation (as advertised) was really disappointing, as was the fact that the manufacturer has no harness kits/converters to solve the main problems with easily installing the unit (see next post). A picture of the kit is below:

Uh Oh - problem

Unfortunately, the kit isn't plug and play for the MDX, and here's why:

• The polarity on the OEM headlight harness is opposite of what the DRL unit expects, rendering it totally inoperative if you try plug and play
• The DRL unit senses that the car is running (and thus turning on the DRLs) through an inductive wire attached to the spark plug wires. But...the MDX doesn't have spark plug wires -- the plugs are snapped directly into the coils for each cylinder.

So, without cutting the MDX's original wires (my primary goal) I had to figure out a way to reverse the OEM harness polarity before it hit the DRL unit, and also had to find someplace to attach the ignition sensor. Here is what's needed to make these mods:

• 2 additional 9006 socket connectors for a custom polarity-reversing harness (goes between OEM harness and the DRL module). These are only available w/female ends, since the male connectors are built into the lamps themselves. Available at any auto parts store.
• 4 24k flat pin connectors (for 14-16 gauge wire) to attach to the wire end of the storebought 9006 harnesses, allowing plug-in to the OEM female harness. Available at Radio Shack in the stereo section
• a wiretap and spade plug for 16-20 gauge wire to attach the DRL ignition-sensing wire to "something""
• heat shrink
• split wire loom to clean it all up and make it look stock

On the left are before and after pics of the inductive sensor wire (intended for sparkplugs) that I added a spade connector to (then heatshrink it). On the upper right is one of the two custom harnesses (9006 plug and flat pin connectors) that plug into the OEM headlight harness (lower right). You just cross the wires when you plug it in to reverse the polarity going to the DRL unit.

For the DRL to operate, it needs to know when the car is running. The inductive ignition sensor wire (meant for a spark plug wire) is intended for that purpose. Since there is no spark plug wire, I had to find an "ignition hot" wire someplace under the hood. The best one I found is the black & yellow "ignition hot" wire leading to the underhood fuse/relay box (passenger side). This is the only readily available, reasonably safe-to-use "ignition on" wire under the hood. All of the fuses under the hood are always hot, so you can't use a fuse tap. BTW this was the only wire that required tapping for the install. It leads to the Engine Load Detector in the fuse box, which basically turns on your battery-alternator warning lamp if the alternator is malfunctioning. There are other "ignition on" wires under the hood, but they're primarily for safety items (e.g. ABS) so I didn't want to mess with tapping into those.

Last One...

I'll leave out the boring part of hooking up the pre-built harnesses from the DRL "master" unit to the "slave unit" on the opposite headlight. I'll also leave out attaching the "red" power wire to the battery. Here's a pic of a decent mounting spot on the passenger side. It's velcro'd and wiretied. I had to order the split wire loom, so I haven't cleaned up all the wiring yet, so it still looks kinda hairy.

FWIW, you could do this whole deal with the fog lights instead of the lowbeams. However, fogs-without-headlights in CA is illegal, and removing the fogs is a bit tougher to do. However, when poking around the engine compartment, I noticed a couple of ideal mounting spots for the control units right by the fogs.

cardingtr said:

What a DRL can do that a pair of headlights can't? At least in a situation that you don't need a DRL, you can switch off a headlight.

If you are responsible, educated driver enough that know when to turn on your lights, you don't need a DRL.

Click to expand...

I was wondering how long it'd be til someone asked "what's the point" but at least it wasn't a "DRLs are evil" post...

I'm not sure how you'd define a situation where you "don't need" a DRL, though, since they're a passive safety device that increase visibility.

This is especially helpful where we live, with many 2 lane, tree lined roads with lots of shadows that make it difficult to see darker cars at all times of day. Bottom line is that cars with DRLs are significantly more visible to other traffic. If the DRLs allow people on the sidestreets to see us better, and keep them from unsafely pulling out in front of us (which occurs too frequently) and requiring me to hit the brakes (or crash) with a wife, kid and dog in the car -- then they're worth the 75 bucks "insurance" right there.

Yea, you could just leave the headlights on all the time, along with all the other running lights. I'd prefer to switch out the just the headlights sooner rather than all the running lights. I also prefer a lower-intensity DRL to avoid any potential glare to other drivers (and the "hey your headlights are on, stupid" flashing from oncoming traffic).

Here's a snippet from the IIHS on DRLs:

Daytime running lights are a low-cost method to reduce crashes. They are especially effective in preventing daytime head-on and front-corner collisions by increasing vehicle conspicuity and making it easier to detect approaching vehicles from farther away.

Nearly all published reports indicate DRLs reduce multiple-vehicle daytime crashes. Evidence about DRL effects on crashes comes from studies conducted in Scandinavia, Canada, and the United States. A study examining the effect of Norway's DRL law from 1980 to 1990, found a 10 percent decline in daytime multiple-vehicle crashes. A Danish study reported a 7 percent reduction in DRL-relevant crashes in the first 15 months after DRL use was required and a 37 percent decline in left-turn crashes. In a second study covering two years and 9 months of Denmark's law, there was a 6 percent reduction in daytime multiple-vehicle crashes and a 34 percent reduction in left-turn crashes. A 1994 Transport Canada study comparing 1990 model year vehicles with DRLs to 1989 vehicles without them, found that DRLs reduced relevant daytime multiple-vehicle crashes by 11 percent.

TheWorm said:

You'd think so, but no. The CDN version has a DRL unit that plugs into a wiring harness (under dash) that differs significantly from the US version. It's not just the harness itself that's different, but the functions/relays etc, too.

Click to expand...

That's really surprising! Makes you wonder what else is significantly different in the Canadian version that requires a different harness? The Navigation isn't available on the Canadian version - that's the only major accessory difference I can think of. Other than that, other than some different labelling - I thought the cars were identical. Maybe a installing different harness for DRL is cheaper than installing a DRL module.

The DRL's on the Canadian version utilize the inside lamp of the headlight cluster (i.e. the High Beam lamp). It's at reduced power, obviously.

DRL's have been required in Canada for a number of years now. I was pretty skeptical when they were introduced but I've since changed my attitude. They really DO make a difference in visibility (i.e. you being seen by other drivers and you seeing other cars) during certain daylight situations: very flat light, low contrast, at dusk, early morning, etc...

Cardingtr: You could switch on your lights when the situation requires it, but the reality is, many drivers don't - and seeing the other guy is as important as you being seen. As you said, any responsible, educated driver would - but it's the other type I worry about. One situation where I think they're valuable is on long stretches of two lane highway. If there's somebody in the other lane, passing a slower car, they're a lot more visible to you, sooner (and you're more visible to them).