tapping noise in rear drivers-side interior

[cngizbleevng]

For the last day or so my wife's 2003 explorer has had a tapping sound coming from inside the car in the rear on the driver's side.

The tapping is not speed-dependent. As long as the key is in the accessory position it will do it (engine doesn't need to be on). Tapping occurs about once per second. There is also a faint whirring sound coming from the same area.

I tried the AC and fan switches in all sorts of positions and the signal lights in all positions, and none of that made the tapping sound go away.

I pulled the plastic trim but there are plastic covers underneath that the sound seems to be eminating from.

Any ideas what this could be?

Thanks!

 

[BigRondo]

Sounds like it could be the rear blend door actuator. If you turn the rear heat/AC off does it go away?

 

[cngizbleevng]

Sounds like it could be the rear blend door actuator. If you turn the rear heat/AC off does it go away?

It looks like you're right. If I set any of the controls that divert air in the rear to the 'mid' position (neither hot nor cold) the sound goes away. It's louder in the cold position than in hot, but there is a sweet spot where the sound goes away completely.

Now for the fix...

 

[BigRondo]

Do a search for "rear blend door actuator", there are a few posts on replacing it. The good news is that it is much easier than the front actuator.