2004 Silverado AC Grinding Noise

[TroySimps]

Hi,

My '04 Silverado makes a weird noise when switching it on or off. It also makes the noise when switching between floor and dash vents. Best way to describe it is a low frequency grinding sound. I'm not talking about the clicking sound that seems so popular with this model truck. It has that too, but this is something different. It does it every time I change a setting on the AC. It does not occur when changing from cold to hot.

My truck also has the issue where it will blow cold at first then blow hot air just on Driver side. Turning the truck off then on seems to fix that.

I've googled around but don't know enough about HVAC systems to know exactly what to search for to help me fix the issue.

Anyone have/know of this problem before and know how to fix it?

[j cAT]

Originally Posted by TroySimps

Hi,

My '04 Silverado makes a weird noise when switching it on or off. It also makes the noise when switching between floor and dash vents. Best way to describe it is a low frequency grinding sound. I'm not talking about the clicking sound that seems so popular with this model truck. It has that too, but this is something different. It does it every time I change a setting on the AC. It does not occur when changing from cold to hot.

My truck also has the issue where it will blow cold at first then blow hot air just on Driver side. Turning the truck off then on seems to fix that.Anyone have/know of this problem before and know how to fix it?

The ac uses step motors now. years ago this was powered by vacuum..

so any issues with temp/vent control would be the step motors and if the air box has debris of critters stuck in there this is what happens.. in texas area lizard critters..

[Tdragone]

I haven't been on this forum in a while; but the issue you want to search for is the 'blend door' My 2002 is now 'affected' http://www.automotiveforums.com/vbul...ght=blend+door