Air con issues

[drone]

It looks like the actuating mechanisms for some of the flaps in the aircon system are goosed as clicking can be heard from the general area on at least 2 of the flaps and possibly a third flap, 2005 c22ocdi estate with the 150 hp engine.
What is it that normally fails is the hexagon shaped drive input on the flap lever the more likely culprit or are the gears on the motor output drive the failure point. Just so I can second guess the spares required as I'd lie to have some on hand before I start taking the dash out to minimise downtime.

 

[MrGreedy]

It can be a broken arm on the motor that drives the flaps.
You can buy spare arms I believe, possibly from Merc.

It might be the connecting splines either on the motor, or on the arm have stripped (or both).

It might be the blend flap motor itself (when my 2003/2004 C class went, it was the internal clutch in the motor, so when you started the car and it tried to do a full swing on startup to calibrate, or whatever, the motor didn't recognise the hard stop position and just kept turning internally, clicking over the clutch or whatever mechanism inside the motor is supposed to hold on to the spindle). I gambled on a 2nd hand motor from ebay for £20 which was fine.

It could be the connecting lug on the blend flap itself has broken, so the arm is no longer connected to the flap.

 

[drone]

Cheers, MrGreedy. when I adjust the temperature with the engine not started, it kind of clicks just the once for each side, also when I switch the recirc on same reaction.
That's why I thought at least two possilby three as the recirc flap appears to work, as does the defrost. just no temperature adjustment.
I'll probably start taking off the dashboard next week and, in the interim order up a couple of flap arms.

 

[MrGreedy]

Make sure you have tested just simply resetting the aircon. I think you just hold down the AC and Recirc buttons down for 3-5s with the engine running, and then the buttons start flashing system runs a full sweep tests to recalibrate zero points on all the flaps. Turn the car off for 15s and then back on again once the reset has completed. It can play havoc if you have your flaps all out of position.

If unsure, there are loads of 30s videos on YouTube showing the correct buttons to press. Also called resetting HVAC system.

 

[rf065]

Make sure you have tested just simply resetting the aircon.

My old 2005 CLK has a similiar problem and I reset it as advised above, problem solved, no need to take the dash out.

 

[drone]

I've tried resetting the flaps, with no success. Also flushed, or rather backflushed, the heater matrix. Some crud came out but nothing worth writing home about.
I also changed the control panel out but with no success either. Tried venting the matrix at the high spots, no luck, cabin filter renewed - no joy. Water pump and thermostat have been changed and the rads been flushed as well, at least they were the first things I did as the car had almost 200,000 miles on it.
All the easy options have been seen off, time to get my knuckles barked, I'll probably renew the brushes on the cabin fan while it's all adrift as they are probably extremely worn.

 

[MrGreedy]

worth a quick cheap try

 

[Petrol Pete]

I think you can buy upgraded links ? Not sure if it is MB themselves who have changed the material they are made from or some aftermarket company makes them.

I keep an eye on these kind of posts because my 2006 S203 is in the 'window of opportunity' for my dash to start 'clicking'......there you go , iv just jinxed myself