...is my '05 possessed?

I'm sure it is something silly, but last night and tonight I was driving with my defroster on. Nothing unusual here in Florida thanks to the humidity. But when I turned it off about three seconds later it knocked repeatedly. I think it was like a five or six count. Sounded like someone knocking on a door.

So has anyone else had this issue or maybe an idea what could be causing it? I tried a search but didn't find anything. To me it sounds like maybe a plastic flap is stuck and ticking loudly when it goes to switch from anything but dash vents. I did a test and when I put it on just the floor then turned it off, it did it. Same for both defrost settings. However, it did not do it on any of the dash settings on the left of the dial.

Thanks for any input gurus.

 

Sounds like the blend door, the plastic flap that directs airflow.

 

Hm. So is this an easy fix or am I looking at a dealership?

 

blend actuator...had one go bad in my Mark VII, they are geared way down, if the feedback switch/pot fails, when it overruns and skips gear teeth its pretty loud. 2 of the 3 in the Mark VII dash are semi-easy, of course the third one was the problem...dunno how many Mustangs use, but probably 3 also. Make sure no mice got in too- my sons mark had sat 3 yrs, mice nested in the blower, made a huge mess- stuck actuators with all the crap in it.

 

Leprechauns

 

Gremlins

 

happens in aircraft too- look at the last one

http://www.funny.com/cgi-bin/WebObje...plane_Problems

 

 

Trunk monkey got in the wrong end of the car !

 

Was wondering how long it would be before you two got involved. Heh. I will start dismantling the car now. Thanks Tim for the heads up.

 

well if taking the hammer away dont fix it...

seriously, I wouldnt dismantle anything just yet- the Mark VII has a test sequence to tell if blend controls are functioning- bet ford included similar in the mustang...call a dealer to see if they can test thru OBDII port or whatever... in the old mark it was holding down certain buttons on the heat controls. also, a bad heat control panel (possibly SJB?) might be the real culprit too- if the feedback pots not getting the signal back from a bad connector or whatnot...ever had the cowl drain thing/wet passenger floor after a storm?

at a minimum, try narrowing it down by going thru each heat control mode and turn temp dial full up/down to figure out which one is causing the trouble- and how to replicate it to tell dealer service guy about...bet someone in here can say exactly what it is, and how to get to it...

edit- found a link- theres 4 motors total- one temp, 3 mode... looks like none are major surgery from the descriptions:

http://iihs.net/fsm/?dir=336&viewfil...oor%20Door.pdf

edit again- I'm gonna save these heres the diagnostics info:
https://themustangsource.com/service...rol_System.pdf

 

I have this same problem. Switching from off or defrost to vent I get the knocking sound. Hope it isn't too hard to fix.

 

Basically if I use the deforest or the defrost/floor setting, the moment I turn it it off there are some knocking sounds. It doesn't do it when I use the vents or the vents/floor option. Doesn't matter if it is hot or cold or a/c... it only depends on which setting I put it on.

Yes I did have the cowl problem with leaves gunking up the plug, had it leak into the car once while driving up a ramp in a parking garage at work, that night I yanked the plugs out and never had it clog up again. That was a couple of years ago though.

Thanks though for the links and I will certainly check them out.

 

What the hell does that mean Frank?

 

Just took my 2012 Mustang in for a knocking noise. When I start the car (whether the a/c is on or not) and then again if I turn on the A/C. I'll try to attach a video. Noise seemed to be behind dash not in the engine.
The car was fixed in approx 2 hours and here's what is on the invoice:

cause: N33
19616B Motor Assembly - A/C DOOR ACTUATOR (Defrost)
Replace (18A318/19E616) - L
1 part # AR3Z*19E616*E MOTOR ASY

No price on the invoice since it was under warranty.

 

Welcome to the forum, jamcruise! Thank you for the info!

Deysha