Ambient Light Sensor

Team Dougherty · June 8, 2012

Hello,

I have a 2002 GMC Envoy SLE. I am looking to activate a relay when it is dark outside. I know serveral things in the truck only work at night. The Perimeter lighting, cornering lights etc... Is there a way I can tap into the BCM harness to energize a relay when it is dark out?

Paul

00Silverado4x4 · June 8, 2012

Welcome, sorry no ideas for your question. Try a search for DRL's or daytime running lights. I remember some threads where people want to wire things up in the same circuitry...If I recall.

MikeNH · June 8, 2012

Good luck, I don't think it will be as simple as you're expecting. I have no experience on them but I've heard from others the electrical architecture of the GMT360 trucks is extremely complex.

Carder09 · June 8, 2012

You looking at adding like a photo-synthetic sensor to differentiate between certain darkness periods? Basically like DRL's? What will this relay be powering?

Team Dougherty · June 8, 2012

You looking at adding like a photo-synthetic sensor to differentiate between certain darkness periods? Basically like DRL's? What will this relay be powering?

I am not looking to add one. I am looking to utilize the one that is there now.

I have a drl killer that that disables the DRLs. Unfortunately this disables the front perimeter lighting. I was looking to put a DPDT relay in that will bypass the DRL killer at night so the front perimeter lighting works. The DRL killer works by cutting the pink/white wire and running it through the DRL killer.

See my poor schematic below. I just need a way to energize the coil at night. I had thought about using the backup light circuit since they come on when unlocking with the RKE. But that means every time I backup the headlights would turn on.

The pink wire is the DRL/Headlight wire.

SouthCo · June 8, 2012

Are DRLs really that bad? Wouldn't it be easy to just take the DRL killer back out? Do the DRLs function as anything else? Just pull the bulbs if not or wait for them to burn out and not replace them.

Welcome to the forum and sorry I don't have the answer that your looking for.

Team Dougherty · June 9, 2012

The DRLs are the low beams in the envoy so I can not pull the bulbs. there is not a seperate fuse for them. Other than lowering gas mileage, burning out bulbs, how many GMCs and chevys do you see with a headlight out?, and just that I feel silly with headlights on in the middle of the day DRLs are not that bad.

There is also and issue with HIDs and the pulsing voltage if I decide to go with those kind of bulbs.

00Silverado4x4 · June 9, 2012

Come to think about it, cant you tap into the DRL circuit to act as a trigger for your relay? It already does the job you want and don't have to dig around in the dash.

Team Dougherty · June 9, 2012

Come to think about it, cant you tap into the DRL circuit to act as a trigger for your relay? It already does the job you want and don't have to dig around in the dash.

How can i use the circuit i am trying to control to control itself? i am open to ideas. everything and i mean every thing is controlled by the BCM. i am just looking for a circuit that is energized at night that i can tap into. like the circuit that dims the radion and the temp and compass in the mirror or turns on the dash lights.

TimmyG · June 9, 2012

Heck my cavalier u could find someone wiyh a programmer and just turn off drl.

Sent from my ADR6400L using Tapatalk 2

00Silverado4x4 · June 9, 2012

Sorry misread what you were trying to do.

Team Dougherty · June 9, 2012

Heck my cavalier u could find someone wiyh a programmer and just turn off drl.

Sent from my ADR6400L using Tapatalk 2

the dealer wont do it. if i knew a rouge gm tech with tech2 scan tool that would be great.

SouthCo · June 9, 2012

The DRLs are the low beams in the envoy so I can not pull the bulbs. there is not a seperate fuse for them. Other than lowering gas mileage, burning out bulbs, how many GMCs and chevys do you see with a headlight out?, and just that I feel silly with headlights on in the middle of the day DRLs are not that bad.

There is also and issue with HIDs and the pulsing voltage if I decide to go with those kind of bulbs.

Your suggesting DRLs lower gas mileage? I don't think so. My 2 GMCs dont burn bulbs prematurely. It's cool if you just don't like them. I couldn't care less as I can't see them from the drivers seat. Before jumping through too many hoops, maybe start offering techs a few bucks to shut the DRLs off. Somebody wants the money. Otherwise, sorry I got nothing and again welcome.

txab · June 9, 2012

I don't believe you ever answered what you are wanting to turn on/off using the ambient light sensor.

Team Dougherty · June 10, 2012

I don't believe you ever answered what you are wanting to turn on/off using the ambient light sensor.

A relay to disable the drl killer. see post #5

Your suggesting DRLs lower gas mileage? I don't think so.

Absolutely. The electricity that lights them comes from the alternator. The more electricity it generates the more fuel the vehicle burns. There are some estimates that DRLs consume ½ mile per gallon.

http://auto.howstuff...onsumption1.htm