Opening Door Causes Buzz

Wxman · October 18, 2017

Hello all,

Just picked up the new truck Monday so I don't have a lot of experience to explain what is happening. Each morning, two so far, when I opened the driver's door the first time of the day I heard a very audible 'buzz' that lasted about 1-1.5 seconds. It happens quick and unexpected, so far, so I haven't been able to place the source much. It is probably coming from outside the cab though. It is very audible.

I thought maybe something with the EVAP or purge, but it happens when I open the door, not at key on or startup. Curious as much as worried. Any ideas?

I park in a locked garage with the truck unlocked if that makes any difference. Has only happened after truck sits over night.

Thanks

On an unrelated note. Where is the external/aux transmission cooler on this model? My 2012 it was right behind the grill and very visible. Haven't found it on this 2017 yet. And yes I should have it and do have KNP code.

BigBadSierra · October 18, 2017

I've hears the fuel pump pressurizing the system on door opens.

I also have the radio make a pathetic drone noise ever now and then.

Mervkirwin · October 19, 2017

I also hear the fuel pump when I go get into my truck when the door is opened. 2017 GMC Sierra hope this helps in some way. Be safe

andyhaug · October 19, 2017

I have heard this as well and it is not the fuel pump. The timing of it seems to be tied to the backlight of the HMI, I hear it start when the screen lights up. The PWM of the backlight somehow gets into the radio, then the radio powers up enough to stop it. Good luck getting GM to fix it. All you will get is "Cannot duplicate customer concern".

tnchevy · October 19, 2017

My 14 model has done the "buzz" when opening the door thing a few times now, seems to be happening more. Mine is coming through the speakers and I think the post above might be right. Mine won't go away though unless I shut the door and open it back up.

Wxman · October 20, 2017

Thanks all. After being ready to listen to it when I opened the door this morning I do believe the buzzing I am hearing is the fuel pump. Only does it after sitting overnight. I will take it as nothing to worry about albeit a tad annoying.