joac21

Hi, my truck has a strange noise when the engine is on (not all the time and it doesnt matter if im stoped or not) i think it comes from the part that blows the ac from the floor.. it sounds strange and i have no idea what it is. and also no idea how to get to that part of the truck to take a look!

any ideas ?

OLD WRENCH

Does it quit if you turn the heater/ac off?

joac21

No... it stays.

kevinkpk

Are you refering to the heater plenum? Thats the duct under the dash that blows air out of the bottom. Is it noise, and vibration, or just noise?

joac21

Yes the heater plenum, i think the sound its coming from there but im not 100% sure..it could be something behind or a bit higher..... its a pretty strange sound like 2 metal sticks clashing into each other and a mouse runing thru the plenum in the background.. everything acompanied by some kind of fluid running thru some hose as well...

oilman71

hey joac 21 i have a 04 silverado with the same noise its drives me crazy the dealer had it 4 times and they can't hear it did you fix it?

joac21

Yes! it was a A.C. Hot/Cold gate actuactor. (not sure if thats the correct translation)

i didnt have the cash to replace it so they stuck it on COLD and deactivate it. i never use HOT air anyway..

just take it to any A.C. service center and they will fix it.

oilman71

Thanks my Hot/Cold gate actuator must have went bad cause heat does not work and no more noise in the dash