Best Answer

The knocking sound could be the doors of the vents closing when you turn it off,they are controlled by vacume.Or it could be the plastic making the sound due to change in temperature. If it is a early to mid 90's Chevy it is most likely the actuator solenoid that controls the recirc or fresh air. If it is it will knock for about a minute and 30 seconds when you start the vehicle and about the same wheen you turn it off.

User Avatar

Wiki User

โˆ™ 2005-12-20 23:53:13
This answer is:
User Avatar

Add your answer:

Earn +20 pts
Q: What would cause a knock sound in the dash after turning off the AC-heat?
Write your answer...
Related questions

Why doe' s my car make a knocking sound when turning?

Suspension is the most likely cause of your knock when turning. The part responsible is probably your tie rod, which is what allows you to turn the steering knuckle. They are inexpensive and easily replaced. You can avoid an alignment fee by being careful with your measurements during replacement.

What would cause a rubbing sound when turning after a complete stop?

most likely a bearing has gone out

What causes singing water pipes?

Singing water pipes can be caused by air that is trapped in the pipes. The air can cause a whistling or singing sound, or it can cause the pipes to knock or rattle.

Does the engine knock with a bad knock sensor?

NO it will not. If you have a knocking sound then you have trouble inside of the engine.

What causes a squealing sound when you turn the wheels completely to the right or left?

The cause of the squealing sound is because you are turning the steering wheel completely to the right or left

What would cause a squeaking sound when turning left or right in a 2003 F-250?

Worn ball joints?

What is the sound of somthing hitting a tree?

A Knock

What would cause a grinding or rattling sound when accelerating from a stop or when turning?

if its a front wheel drive vehicle then it could be the axels

What would cause a Splashing sound while turning or braking?

Low coolant causing air bubbles in the heater core.....

What is the thud when you turn wheel?

If it is a front wheel drive sometimes a bad cv joint can cause a popping sound when you are turning.

Why would a 1992 Pontiac Bonneville SSEi have single knock sound from the back bottom of the motor after the engine rev comes back to idle?

I read that bad motor mounts can cause this knocking sound

What can cause 1997 cadillac catera to make knocking sounds not a pinging sound more of a dud knock also knock comes on most of the time but goes away for a short time?

it could be the belt or pullys check the tensioner assembly

No sound at all turning ignition key?

It is a clicking sound

Engine knocking sound in 84 Chevy?

light slapping knock is a piston knock a loud heavy repetitive knock is a connecting rod Very Bad

What would cause a growling sound when the car is moving?

Most likely a bad hub. Try turning the steering wheel right or left and see if the sound changes or goes away while turning. If it goe away or significantly changes when you turn left it is probably the right hub and vice versa when you turn the other way. If you hear a popping sound when turning it is the constant velocity joint.

When turning the wheels back and forth in your 1997 Malibu the coils seem to be making a dry rubbing sound what could this be?

This sound is cause when the strut top are worn out the need to be replaced can cause coil springs to break. They are pretty expessive 183.00 a side.

What is the definition of the term 'Hark'?

It's a word to present the sound knock. Many words such as hark to create a phantom of a sound knock which can easily be pronounced and spelled without any difficulties.

Have 02 Saturn SL 2 26000 mi grinding noise when turning right or left has new brakes tie rods steering rack all dealer replaced this week still makes grinding sound when turning right left?

Bad wheel bearings usually cause a grinding noise, and are known to only cause it when turning.

Does knock have a short vowel sound?

Yes. The word knock (nok) has a short O (aah) sound as in dock and clock. The short O is seen in words such as hot and stop.

Could a manifold gasket leak cause an engine knock?

No, knocking in an engine is normally more serious than a gasket leak. Depending on how heavy the knock sound is it could be the Big Ends bearings need changing or it if its fainter than that it could be the timing is out. Either way it can cause real damage to the engine and should be repaired as quickly as possible. Have seen exhaust manifold gasket leaks that are described as a 'knock' by inexperienced persons. Normally a knock is piston connecting rod bearings that have gone out.

What would cause a 2002 Alero not to start not even a clicking sound when turning on the key?

security system there is a security reset button in the glove box.

What might cause the waves of sound from a radio to increase in intensity?

Try turning the volume knob up! Or move it closer to your ear.

What would cause a 1991 caravan to not start and just make a fast clicking sound instead of turning over?

When my 1999 did it, I needed to get a new battery.

What is the cause of a loud squeaking sound when making left turns in a 2004 Chevy Cavalier?

If the sound occurs only when turning, (left or right) the most likely cause is a loose power steering belt. First check to see if the belt is tensioned correctly, or in need of replacement.

Does glass amplify sound?

A solid surface like thick glass with little give will reflect sound towards the listener more than it absorbs it. Beware of turning the sound up too with much with thin glass and finding the resonant frequency of the glass. This will cause constructive interference and cause the glass to bend until it shatters.

Study guides

Create a Study Guide