Vito/Viano Aircon Blend flap motor where location?

[ahuncutka]

Hi Guys,

I need a quick help on where to find and replace the air blend flap/motor actuator in a 2010 viano/vito... The issue is that there isn't any cooling on the passanger side. and not prefect on the driver side either.
If i turn the temp dial to hot. It gets hot, but If I turn it to cold 16c setting hardly anything. and there is a grinding sound coming from the middle of the dash as if like a fan was rubbing against something.... If i switch the aircon off, the sound dissapears too.
Replaced the blower fan but not that! So my guess is that its something to with the air blending acuator or stuck flap??? but no clue where to find it.

Can anyone please help on where it is located and possibly how to replace?

Thanks in advance!!!

 

[m80]

I'm not sure of the location but would imagine it to be below the heating control panel.
Another thought is that if someone has removed the panel they may have damaged it or failed locate the keyed square drive correctly on re assembly, these are awkward to do right.

If you go for removal after removing the top screws you need to prise upward from below. It's easy to apply too much force / twist it and cause the vents to collapse. Doing this while unplugging is a skill developed with practice.
With it out you may see what your looking for below it.

This guy has done a lot on Vito's, I know he has a page or two on the panel removal

Mercedes Gen-In - The Mercedes-Benz Vehicle Maintenance Resource

Mercedes Gen-In - The Mercedes-Benz Vehicle Maintenance Resource Mercedes ML W164 V6 Diesel engine tapping under load

www.mercedes.gen.in

 

[ahuncutka]

m80,
Thanks for the reply ive removed everything as suggested... there seems to be no mechanocal issue all flap motors work well from what I can tell.
Ok A little update. hopefully someone can help! Star shows compressor running @ 96% current 0.8A, B12 refrigerant pressure reads between 8-12 Bar B10/6, Evaporator temperature sensor stays between 27.5-34C'
Any ideas where the issue lies? The quite loud hissing sound comes from near the evaporator

Please help!

 

[m80]

What's the AC pressure when sat for some time?
If i check mine now, after not running the engine for a few days I would expect 3 bar, but that may be low even though I do have AC.

Common on these is for the condensor to be holed by a stone while driving.
Hissing suggests a leak of some kind, is this with engine off and while pressure escapes to nil?
There are a couple of fans that run and could mis lead. A small fan is sited below the head unit to draw cabin air past the temperature sensor.
Unlikely to be relevant here, but there is a fan at the bottom of the fuse enclosure to cool the electronics within.

 

[BIG UN]

A hissing would 1st lead you to believe you have a leak but with pressure of 8-12 bar as you have said it wont be that.. so if you have pressure & still no AC it could be yhe pressure sensor that has failed.. it is that that turns on the compressor & is a common fault on these systems

 

[ahuncutka]

Hi guys,
Thanks for the quick reply... When I say hissing... Its hard to describe. at first I thought it was the blower motor rubbing or something... but its not. Ive fitted a new one. The sound comes from below the
Blower from where the evaporator is located but not a leak kind of hissing more like is gas wated to go trough but couldont or something...
The other strange thing is that compressor shows as running @ 96% ?
Can only hear it while engine running If I switch of the aircon button, hissing stops. Switch aircon on, Hissing comes back! But not cooling! This is on the lowest temp setting...

 

[m80]

Probably of no relevance but light on is AC off, it caught me out at regas while the ATS guy was testing under the bonnet.

 

[BIG UN]

Can you hear the compressor engage when you turn the AC on??

 

[ahuncutka]

Yes I can hear the compressor kicking in, and 2 sec later the hissing starts in the dash under the blower motor or thereabouts... Sounds like youre spraying from a pessurized can inside a closed box??? In the centre console
Stationary refrigerant pressure engine off is 5 Bar after letting it sit for 2 hours. Engine on, Aircon running reads 8-12Bar but no cooling All this on Star diagnostic not an actual pressure test.