I have a 2004 gmc envoy and we recently changed batt , and now the a/c want blow thur the front vents but blows thru the floor and defroster fineand we put a new acuator on and now it want blow thru the floor or defroster do I need to recalebrate it ? or could it be something else?

Hi Chris,

I had a similar problem with my 04 Envoy.. here's what to do: Disconnect the (+) battery cable from the (+) post for 30 seconds or so, then reconnect. This process "calibrates the blend door as it cycles it from one extreme to the other. Start the truck and check it out.

If this doesn't work, more drastic measures will be needed. I hope this helps & good luck!

Yep, when you put the new battery in, it blew your actuators, PIA job, but can be done. You can TRY disconnecting battery again, but I'm betting your actuators just blew. Very common problem with our platform, poor design.

the deal is that your a/c doors are now out of calibration. disconnect battery for 1 minute, hook battery back up. now turn key on, DO NOT START THE ENGINE, let it set for 2 minutes, now start engine, it should now work.

If you recently had a weak battery or replaced a battery the HVAC unit will perform a recalibration of all doors. This causes the door motors to be moved full cycle and the mode door will stick some times. Usually this is the problem. The actuator motor will need to be removed and replaced...sometimes they can be recalibrated, but not often.
Good luck, i hope this helps.

most likely there is a napkin in the intake vent under one of the front seats.check to see if there is something in it,use a wire hanger to pull anything out,this should work.

Is it a new vehicle? I had a new vehicle that had the same problem. Answer was that the holes weren't punched out of the vent.

the resister block needs changing... oddly enough i'm unsure of what fan you are saying is not working.... if it's the front.. the resister block is located on the duct work under the dash for the air... near the fan... you will see a connector going into the side of the duct work. two screws and the block comes out... should be fairly obvious for the rear one but it will be near the fan.

Try replacing the cabin air filter.

It may be the actuator not working properly. Should be above the accelerator pedal to the right.

Keeme