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First Post ....... yay!

Hi all, I am hoping someone on here can answer a specific technical question for me. I am not afraid to jump in and get dirty when it comes to working on any car nor am I new to researching. I have looked this site up and down for an answer but can not find one that specifically answers it.

My question is, are the headlights on the Traverse (when the DRL's are on) run on a PWM circuit, reduced voltage or even both?

Like the title states, our Traverse uses the Low Beams as DRL's. I am in the process of updating/upgrading things on the vehicle as I am interested in keeping it as a daily driver for work . Wife and I have owned our 2015 LT (w/ Tech Package) since new and have loved it thus far.
 

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PWM is generally used on vehicles that use the high beam for DRL to dim them to a level that's similar to the low beam.

You should be able to sort this out pretty easily, have your wife start the vehicle with the DRLs on then manually switch to the low beams. No change in brightness means no PWM.

What are you looking to upgrade? I installed Supernova V3 LED bulbs in my low beams 2 years ago, they have been great and maintain a proper cutoff.
 

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Ive always thought that the Traverse used PWM to get the low beams to produce lower lumen output during its use as Daytime running lights.
Also the reason folks have trouble with HID ballasts- when they hook them up to the low beams--- the PWM output causes issues with the ballast start up.
 

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Near as I can tell from the wiring diagram (1st Gen), the DRL's run on the high beams. See wiring diagram below. I'm not smart enough on these diagrams to understand what actually changes the lamp from DRL to normal. There seems to be only one wire to the headlight. But I'm including another DRL diagram. There must be a tie between them, but it's not obvious to me.

Note: X88 = Market Brand Chevrolet; Z88 = Market Brand GMC; W49 = Market Brand Buick; TVD = Headlamps, HID Projector Low Beam, Halogen Projector High Beam

9975
9976
 

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I can confirm every 1.5 gen I have seen on the road in my area (and there are a ton of them) the low beams are the DRL. Most GMs I can think of use the low beams as a DRL... Silverados, Yukon, Traverse, Malibu, etc.

This is in contrast to Honda, who put the DRL on high beams in every vehicle and used PWM to dim it.
 

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My 2010- Low beams are DRL.
Ive replaced plenty of my low beam bulbs....

I put in Silverstars in my High beams... and 11 yrs later-- still the same bulbs.... they simply dont get used much,

Low beams-- different story- theyre always on.... either as DRL or normal low beams at night
 

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Earlier GM used the highs as DRL, S10 pickups come to mind and they ran on reduced power as they were single bulb headlights. I think Saturn's did also.
 

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The wiring diagrams I posted in post #4 are for 2011.
Too new for the highs to be on reduced power, low beams on then. They did it in '90's with the high beams.
 

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Bottom diagram shows labeled DRL lamps. I would assume if highs where used lamps would be labeled high beam and not DRL lamps. That makes it confusing for sure. I'm going with rbarrios that the lows are used for DRL as he has a '10. Programming in BCM may not be illustrated as it's in there grounding the relays in both diagrams. Wiring diagrams show harness colors and connections not control logic. Programming may be mention elsewhere in a manual.
I'm a pro at wiring diagrams, 46 yrs as a appliance tech reading some combined high and low voltage ones not as half as good as these.
 

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First diagram is labeled "Headlights -DRL - Hi Beam (except TSH or T26)" TSH and T26 are both related to steerable headlights.

Second diagram is labeled "Headlights - DRL - Daytime Running Lights." Since there isn't a separate DRL bulb, it's certainly confusing. Why they would call it a Daytime Running Lamp is beyond me. (But what do expect from a company that switched the negative power for years?)

But I've found the tie now and you are all correct, it's the Low Beams.

I'm attaching the low beam diagram. Labeled "Headlights - DRL - Low Beam". Now I can see the connection. On the 2nd diagram above, in the lower right quadrant, there's a wire labeled "712 YE" and an "A" in a triangle. This is the DRL connection to the Low Beams, seen in the diagram below tying into the Left low beam wire below it's fuse. It must power the right low beam by going backwards through the left beam fuse to the right beam fuse.

It would have been nice if they'd labeled where "A" came from and went to. I, too, have done a lot of electrical work in 50 years, including naval aviation, and I'm used to having a hint about where to find an incoming wire or where an outgoing wire can be found.

9991
 
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