I notice much lower air flow regardless of heat or cool and suspect a cogged up in cabin air filter. Can anyone tell me where it is and how to change on a 2007 silverado 2500HD? Thanks, Randy

no,just dirty air in your cabin.

You probably need to change your cabin air filter. If you haven't changed it in awhile then it would definitely be the first place I'd start. You may have also noticed that the air doesn't come out as forcefully as it used to at lower fan speed settings. That's a tell tale sign the cabin air filter is clogged. It's located behind the glove box and very easy/cheap to change. Refer to YouTube for how to videos.

air control heat knob needs removing to determine if its the knob itself, this will just pull off, look at reverse of knod and look to see if the center locating pigot is worn "round" or broken , if this looks ok then the panel housing the knob controls will need removing and then check if the heat control wire is in place, if so trace this wire ,this is a bare steel control wire not an electrical the wire, to the heater box lower dash behind the control panel and see if you can manually move the heat control flap this will look like two toothed semi circular cogs that inter lock , one may have jumped out of place try a little vaseline on the cogs to help lubricate the movement,this is just good practice, after all this i think you will have found the problem.

No, not really. What I mean it is not really directed for the AC, HOWEVER, what it is is a cabin air filter, which of course helps with the ac, heat and vent flow. Which indirectly will allow your ac to flow better and take away some of this wet moldy smells cause from moisture.

This type of filter is normally removable from somewhere in the glove compartment area. It sits in between the fan blower and the cooling evaporator. It provides cleaner internal air and also keeps the evaporator from clogging up which would affect cooling.

However, in that year supposly there is no cabin air filter, but The Haynes manual, although covering 1993 to 2004, says it's in the blower assembly and NAPA is willing to sell a part alleged to be a cabin air filter for a 2001 Altima.Now, i do know there is after market adaption cabin filter that a person can put on, however, in less you had a bad problem it would not be most likely worth the cost and trouble. I hope this helps some. Thanks Mike

One of the Actuators for the doors inside your dash that controls and diverts air might not be working correctly. You may have to either replace the Actuator or Replace the A/C Heater Control. Your vehicle does not come with a Cabin Air Filter.

the air flow does not have any thing to do with the thermostat
make sure you had the right cabin air filter and put in the right dirrection
the air flow is control by three devices calls mode door actuators, if this goes bad then you may not have enough air flow to a certain area

I think u may have an air temperature control blend door problem, the door is moved by a small electric motor, it is stuck in the cold position.

this is caused by the main cabin temp blend door actuator motor, in order to replace it or even check it the dash must be pulled out.