W140 Clicking Noise Glovebox Area

[nullogik]

Hi,

I've had my W140 for two years and ever since buying it there has been a faint clicking noise coming from the glove box or passenger foot well area. I've timed the gap between each click and it is exactly once every 20 seconds. When the climate control system is off it makes the noise. If the blower is on it doesn't appear to click - then again it could be that the noise is drowned out by the blower.

Something must be making it trigger exactly every 20 seconds. Does anyone have any ideas? I've checked for climate control fault codes and it shows no error codes. Any suggestions gratefully received.

 

[stwat]

That sounds sounds like thevduo valves clicking.

 

[nullogik]

The duo valve in the engine bay click/tap very rapidly at much higher frequency than this other noise that I hear.

I was thinking the vacuum switchover valve block perhaps but don't know how to test it.

 

[Joloke]

Sounds like Duo valves to me too!

I Think it was Stu who told me about them?

If you want to eliminate them switch your heating off completely all your controls to Minimum until they click and see if the noise stops?

Not as simple as counting the duration I tried that they can vary

I also turned them on and deliberately got them to click then disconnected the electrical connector whilst it was at its most annoyance and again the noise stopped

Good Grief thought to be able to hear them inside the cheapest base 190 or 124 is bad enough but you guys are hearing them inside 126 and 140 chassis that's appalling when you consider what these cars cost new :fail

When All my other issues are sorted I will devise a way to make a sound enclose around mine as the clicking drives me insane!

Not so much an issue in the current weather