Climate Control

Tapping Noise from Center Vent

Tapping Noise from Center Vent

I have the most annoying tapping in the dash behind the climate control unit. It taps on all settings except defrost, and the up arrow setting. Doesn't matter if the climate control is on or off. Has anyone had this tapping noise? I will have to take out the CC unit anyway to replace either the bulb or the fiber optics in it to make the lights in it work, and when I have it out, I'd LOVE to get this tapping taken care of. Does anyone know what kind of pandora's box I'll be opening trying to find/fix this??

Tim Moeller
88 S4 Silver/Burgandy

Not sure if this helps, but I had a similar problem. Noise was coming from behind the center vent. Turned out to be a vacuum servo that failed. To replace it requires the console and probably the dash to come out. But, I simply capped it. No noise. This approach still required the dismantling of the center console to the point I could get to it.

I believe the orange vacuum line was connected to the servo. So, I guess you could avoid pulling the console and 'cap' it by pulling the driver side console cover and 'pinching' the lines.


Kevin Berez (
'86.5 928S Auto Meteormetallic

Yesterday, I was driving my daughter home in my car, and the tapping was doing it's tapping thing, and she said "Dad, that sound is TOTALLY annoying!!". So, when I got home, I began searching for the tap. I took off the center vent (very easy) and felt around inside until I found it. There's a grate behind the flap that closes the center vent. That grate was being struck by something from behind. I took a piece of cotton padding, lifted the grate slightly with a flathead screwdriver (carefully), and with another flathead, put the padding under the left corner of the grate. This prevents the grate from being hit by whatever it is that's hitting it. Now, in my case, all of my climate control functions properly. I know this isn't the end all fix, and I'll have to eventually figure out what it was tapping the grate, but for now, this was an easy fix that works perfectly, cost me nothing, and took about 15 minutes from diagnosis to fixing. The noise is GONE!

Tim Moeller
88 S4 silver/burgandy/quiet

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