2016 HD Headlamp Install on a 2015 1500 SLT

[jaconrad15]

So everything went smoothly, took out my old headlights and installed the 2016 Sierra HD headlights.

 

With the truck off, I turned on the headlights and they looked great, HID and all. However, when I went to start the truck and turn on the headlights, they only stay on for a few seconds and then flicker and go out.

 

I got the headlights from Gen5diy, and Jarod told me it was a direct swap, no harness required. Anyone know why the headlights would stay on when the truck is off but flicker and go out a few seconds after the truck is started?

 

 

[AaronIROCZ]

Is it anything to do with the DRL's?? I know the 2015's would have pulse width modulated voltage to the headlights when the DRL's would be on to make the lights dimmer. You might need a capacitor installed unless GM did that already and built them into the headlight assemblies. Not sure what the 2016's HD's use for the DRL's.

[AaronIROCZ]

Whoops I didn't see you had a GMC I was thinking the Silverado, not sure on the GMC's to why this wouldn't work properly since the SLT's use the LED strips for the DRL's. Sorry.

[jaconrad15]

Thanks for replying, yeah its strange.. Occasionally they will stay on but most times the headlights flicker and go out when the engine is on.

 

Anybody else done this upgrade or am I the first one?

 

Thanks in advance guys.

[Arth]

For the heck of it can we get pictures of the headlights/the plugs? Do you have an SLT?

 

Also I wonder if the 14v upgrade to the voltage is effecting the HID's.

[morrislee]

It is PWM, sure the harness might be plug and play but the signal is PWM for the pre 2016 trucks for halogen bulbs. This does conclude that the HD has the ballasts built in to the light housing and takes a standard 12v.

 

What you can try is adding a inline (parallel) capacitor, I hope it is strong enough to support the ballasts.

[jaconrad15]

It is PWM, sure the harness might be plug and play but the signal is PWM for the pre 2016 trucks for halogen bulbs. This does conclude that the HD has the ballasts built in to the light housing and takes a standard 12v.

 

What you can try is adding a inline (parallel) capacitor, I hope it is strong enough to support the ballasts.

 

 

It seems to be working off and on, but getting better the more I run it. Still flickers off one out of every 3 times.

 

I'll have to talk to Gen5Diy on Monday.

[morrislee]

 

 

It seems to be working off and on, but getting better the more I run it. Still flickers off one out of every 3 times.

 

I'll have to talk to Gen5Diy on Monday.

Look into a capacitor, out of curiosity, did you ever get the BCM update and changed the bulbs?

[jaconrad15]

No I didn't get it, would that make a difference?

[jhplak325]

Depending on build date of your truck, it could of already had the update from factory to the BCM that ups the voltage to the headlights.

 

The update is for all 2014 and 2015's built before January 2015.

[AaronIROCZ]

Is your truck originally a GMC SLT with the LED DRL's or is it a SLE without the LED DRL's?? If SLE it will require a inline capacitor to filter out the PWM signal and provide a solid 12v signal for the HID's to operate.

[jaconrad15]

Is your truck originally a GMC SLT with the LED DRL's or is it a SLE without the LED DRL's?? If SLE it will require a inline capacitor to filter out the PWM signal and provide a solid 12v signal for the HID's to operate.

 

It is a 2015 SLT with the LED DRLs.

[AaronIROCZ]

This just completely baffles me then, My truck did the exact same thing but it was a Silverado and due to the DRL's were the low beam headlights and although I did have the capacitor it was faulty, replaced it and it worked perfectly till I took them out to trade in. Do the headlights shut off while cranking the engine over to start?? That is the only other thing I can think of, the ballasts loose power or too low of power while cranking and shut down and fail to reignite the bulbs when the engine is running, if that turns out to be the case, a capacitor would fix that problem.

[jaconrad15]

This just completely baffles me then, My truck did the exact same thing but it was a Silverado and due to the DRL's were the low beam headlights and although I did have the capacitor it was faulty, replaced it and it worked perfectly till I took them out to trade in. Do the headlights shut off while cranking the engine over to start?? That is the only other thing I can think of, the ballasts loose power or too low of power while cranking and shut down and fail to reignite the bulbs when the engine is running, if that turns out to be the case, a capacitor would fix that problem.

 

 

When the lights flicker and go out, it is usually about 5 seconds after starting the engine. While the engine is cranking, the headlights do turn off (but this was the case with the stockers).

[Justin Nachazel]

I feel like you aren't listening to anyones posts hah You need a capacitor and that MIGHT fix your problem. One is controlled by PWM and one is not. PWM to simplify, is a way of controlling power supply to a device. To give you an example: If you want to control the brightness of an LED, you would use a resistor or a potentiometer to adjust the level of energy supplied to the LED which is the analog method. If however you wanted to cut those out of the equation, then you would need to use PWM which is a digital method to produce analog results by small pulses. The reason they are staying on is that they are still receiving power, but in pulses not a steady stream. In order to fix that problem you'd need an inline capacitor large enough to accept those pulses and store up power, but also effective enough to let out a constant stream of energy to the bulbs. Basically it has to fill faster than the draw. If anything you might notice it takes your lights 1-2 seconds longer to turn on at first because the capacitors aren't full but after that it should run fine.