shkeller55

I have 108,000 miles on my '98 ML320. Yesterday I noticed a ticking or pumping sound from somewhere in the console. It sounds like it's coming from behind the radio or the climate control knob. I hear it whenever the climate control knob is set all the way over to maximum cold. The ticking is the same speed no matter what fan speed I use, plus it's independent of engine speed. It stops whenever we set the temperature a little warmer than maximum cold. But... it makes the noise even if the A/C is turned off. Any ideas what's causing this? Thanks.

SteveB

My 2003 ML500 makes the same noise. It's a mid frequency dat dat dat dat dat dat dat kind of noise somewhere behind the dash. It's unrelated to engine speed, fan speed, any of the climate control settings, or radio settings.
I've yet to be able to figure it out.

shkeller55

Thanks Steve. I'll probably call the dealer about it. I'll let you know what I find out.

Kar don

It is the purge valve, this has to do with the emissions system in your vehicle. It is normal.

shkeller55

Thanks Al. But... I never heard it in over 6 years of ownership until 2 days ago. If it was normal wouldn't it have always made that noise?

ELDERACER

Does the noise happen 5-6 times then stop- or does it continue?

shkeller55

It continues indefinitely until I turn the knob "up" from maximum cold. At maximum cold the air is also recirculated, but pushing the (separate) recirculate button has no effect on this noise, which is strange.

The dealer says they've never seen this before (and they're a large dealer - Atlanta Classic Cars). I'm taking it to them next Tuesday so they can look at it.

shkeller55

Just got the car back from the dealer. The problem was the blend air flap motor inside the dash; it was going bad. This motor operates a flap that controls the blend of outside and recirculated air coming into the passenger compartment.

The motor cost about $71, but the 6 hours of labor to take the dash apart cost $606. Ouch.

Stiggs

So my ML430 just started making this noise today. Tapping noise coming from right behind the climate control area. Stops when I turn the knob to a higher temp. I guess its the "blend air flap motor" thanks to this thread. I hope the independent shop up the road is cheaper than $606!

Stiggs

Yeah, so I guess $600 is a steal! I called my dealership and they quoted me $1200 to replace this motor! lol
Maybe it's time for a DIY job!

nycnutz

I'm having the same issue with my 2000 ML430. The Dealer quoted this:

For A/C blowing warm air and ticking sound.
Needs new climate control stepper motor.
Part $99.54
Labor $1458.00
Total with tax $1657.54 - DIagnostic fee is $135.00 plus tax if repairs are declined.

Is there anyway to DIY for this part? I really dont want to spend a summer with heatstroke and 5000lbs of empty water bottles in my car.
Thanx guys.

Maj. Dundee

If you live in NYC, I'll do it for you for $500 and you supply the motor.

Stiggs

Do a search here on the forum. I remember seeing a DIY for this fix. Its pretty complicated since I think you have to remove the passenger side airbag. I decided not to do it because you have to take apart the dash starting at the glovebox. I just live with the constant ticking noise now.

nycnutz

Hey Maj. Where r u in NY?

Maj. Dundee

It will be done in the Bronx.

Ajabber64

There is a video on Utube that shows you exactly what to do. If you don't have the time you can remove the glove compartment (after actuator completely fails) and move the white lever back for heat or forward for cold.