I recently purchased a 2004 Chevy Cavalier and this problem occurred after I bought the car of course. There is a loud ticking/banging coming from where the blower motor is under the dash on the passenger side. If you put your hand on the blower motor you can feel the thumping. The ticking/banging remains at a steady pace no matter what the fan speed is set on. The fan speed can be set to off and it still occurs. Also it will do it no matter what position the “mode” knob is in except it stops when you put the mode knob in the MAX position. PLEASE HELP the noise is annoying and am afraid it may damage something else. Thank you.
The MAX position recirculates the air within the car, rather than drawing air from outside. I think the noise is caused by an actuator (vacuum or electric) trying to move a flap within the HVAC system.
Or perhaps the flap is moving back and forth, and ticking or banging each time it moves.
Sorry, but that’s the best I can do from here.
Did anything else change when this started happening?
Have only had the car about 2 weeks and my 17 year old son is driving it. Can’t think of anything noticeable that has changed since then.This just started happening. Thanks for the advice and if you can think of anything else it would be appreciated.
I’ll second mcparadise’s guess - especially based on the MAX position. There are these little flaps in there that control air flow, and it seems likely that your fresh air flap has a problem. It could be as simple as something obstructing the movement so the actuator just keeps trying to move it. Its not a major problem but might require some under-dash disassembly. I would start with pulling the blower motor to get access to the ducts.
Just an added thought. At this time the problem is still intermittent. No specific pattern.
I have the the exact same problem as described by cardud.
Has anyone found a resolution.
The mode control actuator is banging the door against the stop. Sometimes, you can fix the problem by recalibrating the motor control. To do this, either remove the fuse or disconnect battery power for at least 5 minutes and then restore it. The mode control door actuator should go through a recalibration process and reset the limits. If it continues banging against the stop, it may need to be replaced.
I removed the neg battery cable for 10 min, reconnected and the problem remains.
Still loud ticking/banging coming from where the blower motor is under the dash on the passenger side. The battery disconnect did not resolve. Any other solutions to try?
How hard is it to replace the mode control actuator, what all needs to be taken off. Is the part called “mode control actuator” I did a quick search on some part sites and could not find it.
keep looking,the solution is in google,just takes time.
Still not able to find part on-line
is it actually called “Mode control Actuator”???
A gm part name would be very helpful.
Any help with a site that has a diagram of the part and where it is installed?
My Hayes book does not show this part