Started our '09 regular cab truck after work yesterday & heard a "crick/crack" noise from the heater box. Couldn't really tell if it was plastic breaking, or something stuck on one of the blend doors or actuators. I made 2 more stops on the way home & no other noises. This morning when starting the truck, same noise.

I had the AC on, so I turned it off but left the blower running and started slowly turning the control **** from one way to the other to see what happened. When switching from "floor" position to "floor / dash vent" position, I would get a plastic sounding noise, just not as loud. But the functions all seem to still work ok (air goes where the **** says it should be going).

Does this mean I have a blend door failing? Am I doomed to loose the AC again to pull the heater box again (already replaced evaporator & heater core when I was replacing the cam & lifters)?
thanks
Mike S

 

Yesterday noticed that I got similar noises when I shut the truck off. I had turned the fan **** off before turning off the key. You could hear something plastic that crick/cracked (although not as loud) a couple of times. Heater control ***** were set to dash vent only & 90% cold (not to the max cool position). Funny thing is the noises are not consistent. We restarted the truck several times while doing some shopping & only heard the noises on the first start up and the last shut down.
Mike S

 

I have a similar noise in my hvac box every now and then on shut off in my 2500