94 Chevy/GMC Truck HVAC tic-tic-tic noise



There was a caller from a couple of weeks ago that had the very same problem as I have with my 94 K3500 6.5 TD.

When I turn the ignition to accessory I am greeted with a repeating tic-tic tic sound eminating from below my glovebox area for about 10-15 seconds every time the key is turned. It also gives me a corresponding serenade of taps when I shut off the ignition. I can make the sound happen again by hitting the RECIRC button on the dash. The recirc door actually works (you can hear the air flow sound change) and all other functions are operable.

I’d ask a dealership, but their time is money and I plan to repair this myself. Most mechanics I’ve talked to are clueless about it, but it must be somewhat common in this generation Chevy truck.

Click and Clack couldn’t help the poor fellow (or ME!!)

Has anyone else ran into this problem??

What fixed it???


Clueless or not, I doubt there’s anything common (Pertaining to this noise) in any vehicle.

I believe the ticking noise is coming from a piece of debris (perhaps that fell through the fresh air vent) stuck in the blower motor cage.

As the cage turns (when starting and stopping it speeds up and slows down) whatever is sticking out hits against something and makes the ticking noise.

Remember the noise caused by attaching a playing card to your bike with a clothes pin so the card flaps against the spokes?

Perhaps one of those Maple tree ‘whirlybirds’.

Either that or a worn cage bearing.


recirc door servo has broken teeth off sprokets,and is trying to re home itself,replace the recirc door servo mtr.


right on brother




Thanks guys, now there’s an answer that makes sense to me.
It seemed like the recirc door motor was unable to find home (or recognize that its already there and repeatedly hitting the end)
Now its time to actually fix that along with fixing the 6.5’s leaking valve covers (yuck)