May just be a coincidence, but I just installed a new battery this morning in my '11 F150. Now I hear a knocking noise in bottom of dashboard in the area of where the fan and evaporator might be. Cold air is coming out of the defroster vents and barely coming out of ace vents. The knocking continues even with HVAC controls turned off. Any suggestions?
Thanks,
JP

PS I was able to remove hvac/radio dash cover and access the single actuator in my XLT. Dealer had part in stock for $18+tax. Took about 30 minutes to install and button up dash. AC working fine now.

 

I had to remove your second thread as only one per subject is allowed. Just gets too confusing for those trying to help. If you don't get the help in this forum and would like me to move your thread, just PM me.

Thanks

 

Sorry about that, thanks! I thought about thread and decided it might belong in HVAC.

 

I think it can go either place. Just let me know if you want me to move it there or even to the 2004-2008 forum.

 

Was going to suggest broken blend door or gear controlling it, but if you hear knocking/thumping even with everything in off...I bow...

???

 

I am reading about HVAC while spurs/mavs battle it out. Look like newer vehicles use a different type of actuator. I dropped glove box and I think I can see and feel actuator behind radio that is knocking. No to figure how to remove dash.

 

Make sure you didn't break or knock off any vacuum lines when you changed the battery.

 

I have a 2011 XLT model. There is only one actuator and it's located to the right side of the dash and to the left of the glove box. I found a video on YouTube that showed how to remove the center section of dash that held the hvac and radio controls. Then removal of radio unit gave me room to remove the actuator. There aren't any vacuum lines in these newer systems. Luckily, dealer parts departments were open til 5. One dealer quoted $50 and another quoted $18 some plus tax. Picked up new actuator and had it installed and buttoned up in 30 minutes. Works like new without any noise. I disassembled old actuator and found one tooth broken off one of five gears.