Make DRL Turn On With Parking Lights

[ShookieJay]

I just purchased a set of Spec-D headlights with the DRL LED fiber optic bar for my 2003 Tahoe. The way they're meant to be installed is tapping into the DRL wiring, but I want the bars to illuminate when the parking lights are on too. Basically I'm looking to have them act as DRL, but also be on at night when the headlights and/or parking lights are on. My initial thought was to tap off both the DRL and parking light wiring and putting a diode on both wires to prevent them from backfeeding each other. Can anyone confirm if this is the correct way to go about it? Or better yet, if someone has a wiring diagram detailing the entire front lighting harness/BCM, I would be able to work it out on my own. Thanks!

 

[89Suburban]

I just purchased a set of Spec-D headlights with the DRL LED fiber optic bar for my 2003 Tahoe. The way they're meant to be installed is tapping into the DRL wiring, but I want the bars to illuminate when the parking lights are on too. Basically I'm looking to have them act as DRL, but also be on at night when the headlights and/or parking lights are on. My initial thought was to tap off both the DRL and parking light wiring and putting a diode on both wires to prevent them from backfeeding each other. Can anyone confirm if this is the correct way to go about it? Or better yet, if someone has a wiring diagram detailing the entire front lighting harness/BCM, I would be able to work it out on my own. Thanks!

View attachment 415373

Do you have a link for these so I can inspect the parts?

 

[ShookieJay]

Do you have a link for these so I can inspect the parts?

Here ya go!

 

[89Suburban]

Here ya go!

So the wiring for the bar lights are just cut ends that you have to splice?

I just got a set of knock off Spyders and I have those bar lights wired to the parking light circuit. And I delete my factory DRLS and replace with park/turn lamps. I also pulled the fuse for the DRLS. That's just me though.

 

[ShookieJay]

So the wiring for the bar lights are just cut ends that you have to splice?

I just got a set of knock off Spyders and I have those bar lights wired to the parking light circuit. And I delete my factory DRLS and replace with park/turn lamps. I also pulled the fuse for the DRLS. That's just me though.

Yes, they're flying leads that need to be spliced.
I would prefer to retain normal functionality of park/drl, just with the addition of the bars for both.
I know the parking lights are controlled by a relay in the BCM, but what about the DRL? My only worry is if the the DRL control is solid-state it would cause undesirable side effects...

 

[89Suburban]

Yes, they're flying leads that need to be spliced.
I would prefer to retain normal functionality of park/drl, just with the addition of the bars for both.
I know the parking lights are controlled by a relay in the BCM, but what about the DRL? My only worry is if the the DRL control is solid-state it would cause undesirable side effects...

Ok I follow you now, you wan them to come on with the DRLS and the parks. That's next level for me. Hopefully someone knowledgeable will help you out.

 

[ShookieJay]

I appreciate you taking the time to help. I managed to get ahold of a more complete set of wiring diagrams, and it looks like both the DRL/parks are controlled by separate relays in the BCM. Now that I know there's no electronic funny business involved, I'm gonna go with my original plan of splicing into both circuits using diodes. I'll report back with the results. If it works the way I want it to, maybe I'll even write up a tutorial

 

[Mean_Green]

Is there a reason not to go fully separate? 12V to a relay that only comes on with IGN in Run. The relay switches hot 12V to the lights. They should be on anytime the vehicle is running no matter what the other lights are doing. Option to add a switch to disable them if desired.

 

[ShookieJay]

Is there a reason not to go fully separate? 12V to a relay that only comes on with IGN in Run. The relay switches hot 12V to the lights. They should be on anytime the vehicle is running no matter what the other lights are doing. Option to add a switch to disable them if desired.

That's a good point. I had considered a relay, but it wouldn't be as cool because they wouldnt come on when I unlock with the keyfob

 

[S33k3r]

Man, love your thinking! Definitely looking for any progress you make.

A word of caution: I don't know how long those tube LEDs are going to last, so you might want to keep that in mind. Can the LEDs be replaced when they burn out?

Those concerns are why I dislike the tubes, and/or halos.

 

[ShookieJay]

Man, love your thinking! Definitely looking for any progress you make.

A word of caution: I don't know how long those tube LEDs are going to last, so you might want to keep that in mind. Can the LEDs be replaced when they burn out?

Those conserns are why I dislike the tubes, and/or halos.

I will definitely update the thread when I get around to doing it, probably won't be for a while tho.

As far as the LEDs, they are sealed in the housing. They can be replaced, but not easily. It would require disassembling the housing and desoldering/replacing the individual lights on the circuit board. As for longevity, I would expect them to last a very long time. LEDs have an extremely long life, it's usually the resistors that fail. Some manufacturers use the cheapest possible components, which often means using an undersized resistor which will eventually burn up and cause the LEDs to stop working.

FWIW, I've had the matching set of tail lights installed for over a year now and they're still going strong.

 

[tooleyondeck]

I ran mine into my turn signals (parking lights) that way they come on when I hit the fog light button. I drive around like that most of the time with just the LED bars and fog lights on.

 

[ShookieJay]

UPDATE: I finally got around to installing the new headlight housings over the holiday weekend, and I gotta say, I'm thoroughly impressed with both the look and light output/beam pattern at night. I kinda rushed the installation and ended up using the tap splice connectors that came in the box (yes those dreadful things). It's only temporary until I complete the rest of the wiring. As of now, the LED bars are wired into the DRL circuit so they only come on during the day or when I unlock the doors with the keyfob. I still need to integrate the parking light circuit so they'll come on at night too. I decided to use a 5-pin relay instead of diodes like I originally planned. I'll attach a drawing of what I'm thinking, and a few pics of what they look like on the truck. I'll post another update when its all finished.
Happy new year everyone!