I have a problem with my 2004 Impala windshield defroster. When I turn the selector to defrost I do not have any air coming out of the defroster windshield vent, but I do have air coming out of the side window vents. The blower is blowing but air is not coming out of the defroster vents, but does come out of the dash vents and the heater floor vents. Another thing I noticed if I set the control to blow out the dash vents it does blow out, but when I move the selector up one notch to the dash/floor position the air now blows out even faster from the dash vents. Anyone know whatis causing thisproblem?

I should note that I just had work done on my impala due to a leaking intake gasket causing oil to get into the coolant. The shop replaced intake/valve covergaskets, replaced thermostat, flushed cooling and fuel systems, new plugs, oil and coolant. I had not noticed this problem prior to this repair, so I'm wondering if the problem might be related to this repair. I don't know if the heater controls are electric or are vacuum controlled. I did check in the engine compartment for any loose vacuum hoses or wires and I did not see anything out of place. Any help with this issue will be greatly appreciated. Thanks.

 

im not 100% but I think it is electrically controlled. That is odd though its not blowing through the dash.

 

Your damper motor has quit working or either the switch that controls it has gone bad.

 

It is blowing through the dash vents and floor vents, just not through the defroster vents.

EvansBlue, Are there separate damper motors for the dash/floor vents and the defroster vents? I am able to switch the selector switch and change where the air blows out, but just not out the defroster vents. I am leaning towards the switch being the problem, since there's the selector issue I mentioned earlier,where the dash vents blow harder whenthe selectoris set to the "dash-floor" setting then when it set to just the "dash" only setting.

 

I beleive, I may be mistaken, that there is one damper motor for all three. It could be that it will not move into position or its in a bind.[/align]

 

I would guess that battery voltage was either removed or lost during the repair. If it is and once power is restored the actuators need to relearn. They do this on their own but if the controlls are touched while learning the process will be aborted and improper function will follow.

Try removing power from the module by either (make sure the key is turned off and removed first) disconnecting the negative battery cable or removing fuses HVAC BLOWER from underhood fuse block, A/C CRUISE from the left instrument panel fuse block and DIC/RKE fuse from the right instrument panel fuse block.

Once power is removed let it sit for 5 minutes or so and then re-apply power. Then turn the key on for 2 minutes and do not touch anything, if you touch the HVAC controlls you will abort the learn. Next turn the key off for 1 minute. Now go for a drive and see if everything works.

If it doesn't you wasted 10 minutes and no money, if it does you got a fix for free.

 

Well I tried using the defroster this morning and it now works. Now I'm afraid to move the selector with winter fast approaching.

 

yea you don't wanna freeze yourself and just keep the defroster on. haha