[ryo-]

I've been noticing a weird buzzing near the left driver-side air vent area. it is intermittent and usually lasts for about 30-60 seconds. it sounds like a fan blade hitting a wire as it spins... I believe it is the heater, or circulation, as when I have the AC on, there is no noise and it only happens when there is no cold air blowing through the vent.

does anyone have any ideas? it does not bug me that much to warrant me dropping off the car and not having it for a couple of days.

[danallxt]

I had that at first, and it just went away after a short while.
Dunno what that was all about.

[RockCrusher]

Originally Posted by ryo-

I've been noticing a weird buzzing near the left driver-side air vent area. it is intermittent and usually lasts for about 30-60 seconds. it sounds like a fan blade hitting a wire as it spins... I believe it is the heater, or circulation, as when I have the AC on, there is no noise and it only happens when there is no cold air blowing through the vent.

does anyone have any ideas? it does not bug me that much to warrant me dropping off the car and not having it for a couple of days.

Had a car that manifested something similar. Thought it might be a bad air door motor. Tech said it is possible but it could be a relay buzzing. The noise only lasted a while and only upon cold start. The heater/AC system worked fine from 0F to 119F ambient temperature.

In your car's case that there is no air blowing through the vent suggests it is an air door motor.

Might mention with this car I had a couple of other issues that were not severe enough to have addressed -- the noise I mentioned above, misfires on cold start to name the ones that come readily to mind. I learned to live with the noise and the cold start misfires I avoided these but not letting the engine idle after cold start but within in moments just easing the car out of the carport and just driving off, albeit as is my SOP limiting RPMs to under 3K and avoiding heavy application of the throttle until the engine is warm.

Then the alternator failed. Got a new (factory) alternator installed. Noticed right away the battery voltage gauge was reading >14V while with the old alternator it was a cold day in Hell when the gauge read even 14V. A good day had the voltage at 13.9V.

Not a big difference to be sure but over time I noticed the buzzing from the A/C/heater area was gone and so too when I tested for this were the cold start misfires.

I've had cars since that even with a healthy alternator (and battery) manifested issues that proved to be related to a low battery low due to lack of sufficient use. More use kept the battery topped up and the issues vanished.