Hi-
i've got an 01 crew cab-(just got it)-runs great but when you turn on the heat the fan has all it's speeds but the air flow out the vents is not what it should be--in fact it's WAY less than it should be. the directional selector control seems to be functioning, a/c compressor will come on if asked to, it just seems to be an air flow restriction.
any ideas?? (it's really cold here today)
thanks
rich
btw--I have the dreaded "engine tap"----drove me crazy until I found this site and read all your feedback and the tsb. now it just ----drives me crazy!

You need to change the cabin filters...

Passenger Compartment Air Filter Replacement

Removal Procedure


http://service.gm.com/engif/000/000/687/687390.gif

<LI type=1>If equipped, remove the IP sound insulator. Refer to Insulator Replacement - Instrument Panel (I/P) in Body and Accessories. <LI type=1>Remove the filter access door screw. <LI type=1>Remove the filter access door (1) from the HVAC module.
Remove the passenger compartment air filter (2).
Installation Procedure


http://service.gm.com/engif/000/000/687/687390.gif

<LI type=1>Install the passenger compartment air filter (2). <LI type=1>Install the filter access door (1) to the HVAC module. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

<LI type=1>Install the filter access door screw.
Tighten
Tighten the screw to 1.6 N·m (14 lb in).

If equipped, install the IP sound insulator. Refer to Insulator Replacement - Instrument Panel (I/P) in Body and Accessories.

didn't even know i had such creature comforts. I'm going out now and find this sucker!
thanks again Max
rich

how'd you turn out?
Jason

I had the same problem, lol

thanks to Max i found the filters---totally loaded up--replaced with new and perfecto!!! it'll blow my shoes off.
thanx again
rich
now if you could just get rid of that tick,tick,tap, tick, tap

There is a fix for the tick noise that GM just approved... There is a 1/2 black knob located on the dash, just to the right of the steering wheel. Turn it clockwise 1/4 turn, and the tick goes away:D Glad your heater is fixed:ro)

that, or i could take my wife every place i go-:t

Now that is funny no matter who ya' are):h

ROFLMFAO......That's funny because that little knob solved my ticking problem too):h