Heater Box Vacuum

[BadFord]

I have researched several threads regarding HVAC vacuum (quite overwhelming), but have not found my exact issue. If it is covered elsewhere, please let me know.

Every time I get in the car and start it, I hear an HVAC door close on the passenger side.

Is there a common issue causing this? Is this possibly a check valve, or the dreaded o-ring issue?

I have not noticed any issues with the heat output, but I haven't really checked.

Thank you in advance from a NOOB...

[gdmjoe]

BadFord...
WAD (Working As Designed). Just the HVAC (re)registering/setting to the home position.

To help stop the noise, before turning the ignition -off- ...



Turn-off all/any climate control functions.
Turn-off the HVAC by depressing the OFF button.
Turn-off the ignition.

.

[BadFord]

Thank you!

[SilverPhoenix]

Just so you know, the dreaded o-ring issue is when air comes out only through the defrost vents, regardless of what the ETAC is set for. It's not a question of IF this will happen, but WHEN. I'd get in touch with FastBlackMerc as he can replace the hard rubber o-rings (that eventually crack, thus causing the issue) with silicone ones. I had him do that to mine 12 years ago and haven't had any issues since.

[BadFord]

Thanks for the info!

[fastblackmerc]

Just so you know, the dreaded o-ring issue is when air comes out only through the defrost vents, regardless of what the ETAC is set for. It's not a question of IF this will happen, but WHEN. I'd get in touch with FastBlackMerc as he can replace the hard rubber o-rings (that eventually crack, thus causing the issue) with silicone ones. I had him do that to mine 12 years ago and haven't had any issues since.

Thanks Kyle!

I will also upgrade the fan wheel and button lights to LEDs.

I also repair LCMs, BCM's and lots of other things.

[BadFord]

Thanks Kyle!

I will also upgrade the fan wheel and button lights to LEDs.

I also repair LCMs, BCM's and lots of other things.

Good to Know!!!