Low beam Headlights seem to

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HoldOn SV

Re: Low beam Headlights seem to

Post by HoldOn SV »

I'm not certain because I don't have the wiring diagram, but thought if there was a failure in the ambient light sensor circuit, the BCM would default to full headlamp intensity.
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Car54
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Re: Low beam Headlights seem to

Post by Car54 »

Had a few min during lunch today… here are the pics of the wiring mess passenger side between the fuse panel and headlight
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Turbopowered68
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Re: Low beam Headlights seem to

Post by Turbopowered68 »

TTT
Update?
2014 Caprice V8
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1986 GN
212/212 Roller cam, 1.65 HR Rockers, 60-1 turbo, XFI 2.05, E85, Ebay Front mount IC, Husek Built TH200-4R trans, 3.42 gears 3800# .
1968 Chevelle
LQ4, 4L80, 12 bolt w/3.42 gears
Car54
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Re: Low beam Headlights seem to

Post by Car54 »

Had my friends snap on tool connected to the car. It’s showing a signal to the BCM.

So honestly not sure what’s going on.

My understanding is the DRL, is located top of the headlight and…not… park of the regular bulb.

That switches accordingly with the sensor on the top of dash.

Until I can get it to a reputable shop or stealership that knows what to look for, im dealing with it
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rcg530
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Re: Low beam Headlights seem to

Post by rcg530 »

The DRL functionality uses the low beam bulb with a reduced voltage/brightness to provide the DRL feature. The voltage level is increased to the low beam bulb to provide the regular brightness level for that bulb.

I have a video on my channel from early 2020 just after I updated the BCM with GM SPS to enable the automatic headlamp / DRL features as well as enabling the rear door window switches. You can see the low beam bulb is turned off for the DRL feature and it increases in brightness a small amount for regular non DRL mode.

https://youtu.be/0uBRSXwEu2s
2014 Chevy Caprice PPV | RetroCarGuy530 YouTube Channel
Car54
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Re: Low beam Headlights seem to

Post by Car54 »

rcg530 wrote: Sun Feb 06, 2022 4:34 pm The DRL functionality uses the low beam bulb with a reduced voltage/brightness to provide the DRL feature. The voltage level is increased to the low beam bulb to provide the regular brightness level for that bulb.

I have a video on my channel from early 2020 just after I updated the BCM with GM SPS to enable the automatic headlamp / DRL features as well as enabling the rear door window switches. You can see the low beam bulb is turned off for the DRL feature and it increases in brightness a small amount for regular non DRL mode.

https://youtu.be/0uBRSXwEu2s

A huge thanks, I’ll look at the car more closely this week, it’s currently on lone to my dad.

One thing you mentioned is the auto headlight feature. Never looked closely at the DIC center but my headlights always turned on & off automatically.

Not sure if this feature would have anything to do with the headlights not going full brightness.
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rcg530
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Re: Low beam Headlights seem to

Post by rcg530 »

Car54 wrote: Sun Feb 06, 2022 6:01 pm One thing you mentioned is the auto headlight feature. Never looked closely at the DIC center but my headlights always turned on & off automatically.

Not sure if this feature would have anything to do with the headlights not going full brightness.
DRLs and auto headlamps are one feature in the BCM related to RPO code "VVS". Most Caprices (at least 2014-2017) will have RPO code / feature VVS enabled in the BCM which disables the automatic headlamp feature and the DRLs. I had to disable RPO code VVS in the BCM to enable those two features.
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Car54
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Re: Low beam Headlights seem to

Post by Car54 »

Checking my RPO codes I don’t have the VVS code.

Can the upfitters turn this feature on & off?

Is there anyplace else I should be looking inside the car or under the hood? Wondering if the removal of all the police equipment from the center consol they omitted reconnecting something.

Have to get the car back home 1st, its not in my hands at the moment but hopefully later in the week it will be.

Im not a computer/car guy. If I cant figure this out myself, I would like to be able to talk to a shop or a tech at the dealer and give them an idea where to start.

As you all know these cars are not that well known even at the dealerships. When I called the dealer in inquire when they had an opening for the recall on the seatbelt, the person on the phone kept saying there wasnt a recall or tsb on the SS! Click…
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rcg530
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Re: Low beam Headlights seem to

Post by rcg530 »

The 14-17 Caprice BCM can be configured to have VVS configuration (RPO code) enabled which turns off the DRLs and automatic headlamps or the BCM can have VVS disabled (not listed on the RPO list) and that should mean the DRLs and automatic headlamp feature should be enabled.

I used the older GM SPS software to disable VVS in my 14 Caprice's BCM to re-enable the DRLs and automatic headlamps. That should also be doable with the newer GM Techline Connect SPS2 offering (replaces SPS), but the last two times I tried to use SPS2 there was still missing calibration file info missing for the 14 Caprice's BCM causing it to fail (video on my channel about that too).

The upfitter could have messed with the headlamp wiring, but you'd have to start following the wires coming out of the headlamp assemblies to see if you see any cuts/splices/odd wiring to see if they were changed. My situation was easy in that I only had to reconfigure the BCM's config options to get DRLs and automatic headlamps turned back on by turning off the VVS configuration option.
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Pursuit
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Re: Low beam Headlights seem to

Post by Pursuit »

When I was working on a circuit pathway for my fog lights, I used the DRL circuit. I have a 2011 9C3. I did have the DRL signal (a grounded signal from the BCM) removed from the BCM software. I had the fog light input and output activated in the BCM software. The BCM fog light output is a grounded signal. I added the fog light circuit from a headlight switch that had the fog light option to the fog light input for the BCM. I then added the fog light BCM output (different pinout than the DRL) wire and pinned into the BCM harness connector and ran that output wire to the DRL relay. It is located in the front left foot well. The supply voltage to that DRL relay is 12v. Following the old DRL circuit to the under hood fuse box I separated the DRL circuit from the low beam circuit. Those two circuits are combined to the one low beam circuit within the fuse box.
I know that this is a long way around for an explanation, but given the circumstances, the DRL is not a reduced voltage. And, maybe this would help future factory style fog light installs?

Regards,

Maurice
Maurice Sheil

mhsheil@gmail.com

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