My '94 does the same thing, if you disable the heater air conditioning circuit it goes away. I believe it to be an air dam inside the case where the heater core is. I just refer to it as The Heartbeat of America
It is an Air plenum door This is a door inside the unit that houses the evaporator core it redirects air flow on the floor side of the passenger compartment. I have a 94 chevy truck that does the same thing. To expensive to fix so I just live with it. It only last about 10 to 15 seconds when either starting the vehicle or turning it off. To confirm this have the caller if possible perform this simple procedure. While the vehicle is running have him (while the AC is on ) activate the AC recirculation button and the same thing should happen when activating this or deactivating this. Hope that this helps somewhat. I have heard that one can disconnect this door and the only thing that happens is that no heat is transferred to the floor on the passengers side. Which is a good thing if mother in law is sitting on that side and it is freezing. Marco Baton Rouge La
Thanks for the info on repairing typos
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I worked for GMC for many years. That sound is a bad actuator for one of the blend doors. I have replaced hundreds of theese things. Thare is nothing in the fan or ducts. Theese actuators are a common failure. Most are simple to replace 2 or 3 hex screws and a eletrical connector. I am just surprised Tom and Ray have never seen this in their shop. If there was a object in the ducts the noise would remain constant and not stop after 15 seconds. It would also vary in pitch and tone as the blower speed changed. I believe the caller was describing the blower motor when he made the call. He needs to find the connector for the actuator and unplug it to verify which actuator failed. Here is a link with a pic of what the actuator will look like. http://z.about.com/d/autorepair/1/0/a/G/57435881.gif
The truck in question is a 1996 Chevy. Nevertheless I looked under my 2000 Chevy Silverado 2500 dashboard to see if I have one of these top hat shaped thingies on the firewall behine the glove compartment.
Alas, I can’t tell, because they have completely encased the passenger compartment side of the firewall with some covering. No telling what is behind it.
I had a sound like that in my Ford Windstar. The Windstar has a plastic box which opens and closes the door in tha heat/AC system. The box has a little motor which turns a gear which caauses the action and also operates internal swithes which shuts the little motor when the vent is all the way open or closed. The gear in my Windstar lost several teeth so the motor did not complete the action and shut itself off; it just kept spinning making the sound as it hit the broken gear. The little module cost me $10 at the junk yard. Of course, the Chevy problem may totally different than the Ford but who knows. Good luck, Michael
I'm surprised that you didn't know this one right off, anybody with the nick names of click and clack should consider it part of their name sake. Does that mean I get your job? (Ok, I'll settle for this weeks pay check or even a Tee shirt size XXXXL) The clicking (ticking) described comes from under the dash board, on the passenger side, behind the glove box. It can also be heard from the engine compartment side of the firewall on the passenger side. As someone else mentioned earlier, it's a drive motor drive gear hitting on a busted nylon gear tooth of an actuator gear for the door that is part of the flow through air system, although the flapper door is sometimes part of the heater and/or air-conditioner system. It's a fairly easy fix with metric sockets and a screw driver or two, also needle nose pliers to disconnect plug in wire spades. You can usually get the motor for $100-$200 at a dealers or $40.00 from Car Quest if you can get a parts man who knows his stuff as they usually grind the part number off the motor so you have to go to the dealer. Because this part actually does something vital for the ventilation in the vehicle, I suggest you fix it rather than try to disconnect it, besides, after you get inside the vehicle standing on your head with your right arm wound around your left leg trying to reach the little mother, most of the battle is over! Have fun!!It’s a metronome, it keeps the engine in time.
Tom and Ray
This is very common, I have had a vehicle 96 Blazer that was repaired along with 4 others that I have repaired at our shop. The recirculation door for the heater is ran by a actuator(little motor). It is mounted on the HVAC plenum. With each key on and key off cycle it is cycled. Inside the actuator there are plastic gears that chip out, what you are hearing are the gears jumping and not moving the rec. door. A magnetic socket for the 3 screws that hold in place, along with small hands will help. Good luck Nate
The ten inch diameter object is the cabin air blower motor, located under the dash on the right side. The ticking sound is an air valve’s motor that has failed. Not an easy task to remove and repair/replace…I just disconnected the lead to the valve’s motor. I do not remember the specific function of the valve (e.g. direct vent air vs. heated air) but whatever the function was I certainly do not miss it. I still have heat and A/C.
Hope this helps,
BobT
I have a 1995 Honda – the automatic atenna no longer goes up or down by itself! But … every single time I put the key in the ignition and turn the first turn, I get the same clicking noise I heard on the radio yesterday! It lasts about 10 seconds … and then, when I turn the car off, the same noise occurs. I was listening to the show yesterday while driving, and I said … “that guy has an automatic antenna and doesn’t KNOW it.”
By the way, I’m 70 years young … and female.
That is a possibility, if that truck has a power antenna but I know none that have that feature.
My neighbor’s Chevy pickup (in Atchison, KS) makes the same sound exactly and I have often wondered what it could be when I borrowed his truck. My dad was a mechanic and had his own garage for many years, so it’s very unsettling to hear a noise like that without knowing what it could be. My brother told me it was a vacuum actuator that controls the air flow from the a/c, defroster, floor and dash vents. There are some plastic pieces inside and when they break, it makes a very weird sound. I also noticed, like Rick, that it was upon turning on and turning off the car.
Hey guys:
I used to have a similar truck, and recall the “top-hat” structure in the passenger footwell housed the blower fan. Sounds like perhaps it is obstructed? A broken vane, perhaps? It would be easy to verify by changing the fan speed and listening to if it has an effect on the frequency of the sound…
Hope it helps!
as correctly stated it is the accuater that controls the recirculation door for the heating and ac cooling system.
the simple fix is to unplug the connector to it as i did. you have to decide wheather you would like to have fresh air or recirculated air before you unplug it, because it will no longer move.
I own a 94 CMC pick which have the same problem. I have lived with it for 3 1/2 years. The question is how do I fix it? without spending too much money. Is it something I can fix myself?
Thanks!
Hey Lunatic!
I have the same problem in my '94 GMC pickup. Your symptom matches exactly with my experience. I have lived with it for 3 1/2 years. The question is how do I fix it? Let me know. It scares people when I give them ride.
Thanks
Ok…so i have a 94 suburban and been going crazy with that ticking soung coming from the heater …Yes it is the door that opens to bring fresh and close to recycle the air like for the AC… I believe when you switch off, the door close and would try to open or close when you turn the switch on, depending on how you left the setting. because of the unknown malfunction the door is trying to open but is slipping…Hence the ticking sound.
if you want to get rid of that sound…try this …with switch on press the MAX Button…if the noise stops then we are on the right track…Remove the dash around the steering wheel to get to the back of the AC MAX and OFF buttons.
there is a wire harness going into the back of it…Cut Or Remove the PINK WIRE …its the only pink wire with a white stripe…thats it No more ticking…Mind you…the door is now stuck on closed.! no more Fresh air.
It works for me…