variable air con fan speed

[sawman]

my car has the digital climate control system, This afternoon, the fan seems to have adopted a life of its own. with the aircon on auto, the fan speeds up as normal, with the black indicators matching the speed. but I notice that sometimes the speed fluctuates whilst the indicators havent changed.

It seems to do the same in regular mode too.

I think the system needs regassing as its not very cooling when trundling in town, although it seems ok on a faster run.

Also I will change the filter this week - I dont suppose its been done for a while (judging by the state of the engine air and oil filters!)

would a cruddy filter cause the fan to struggle? or is there somewhere else to look?

 

[flango]

Its the regulator at the side of the blower motor that is probably causing the trouble

 

[Kajtek1]

On the other hand the car automatically adjust the flappers to direct the air flow depends on sun exposure, so what you can hear as speed change can be flow change?

 

[sawman]

Ah, so yesterday the blower sounded like something had got sucked into it - this seemed to clear after a min or so but today it seems like the blowers not working - is this likely to be the regulator or the actual blower?

 

[SL300-24]

I think if you put a meter across the plug that connects to the blower motor and you get a 12v reading it will be the motor.

 

[sawman]

I havent got around to investigating yet. But if something had been sucked into the motor would it trip out?

 

[E55BOF]

Its the regulator at the side of the blower motor that is probably causing the trouble

Mine (W210 '98) has come out in sympathy with the same symptom, but additionally, the air coming out of the centre dash vents is warmer than that coming out of the dash side vents. Could the two symptoms be connected? (I can't see how, but having had experience of the climate control in my Saab 9-5, almost anything might be possible... )

Also, the electric aircon fan in front of the condenser drives only itself - the belt to the other fan has dropped off. Would that be a more likely cause of the failure to cool the air effectively while idling in a traffic jam at 30 deg C ambient?

E55BOF

 

[sawman]

It's started working again now - Things like this wind me up

 

[nigel cross]

I'll second the regulator part of the motor on its way out, not to bad 2nd hand and only a few minutes to change.

 

[sawman]

spent a while looking at regulators in the 'net last night. I have yet to find one which is compatible with my w202 c280 estate - all the listings seem to quote almost all other variants = can anyone help with the part number?

 

[E55BOF]

It's started working again now - Things like this wind me up

Mine hasn't... It's not cooling at all now, but the fan speeds are OK for the moment. The only stored fault code is E B1424, which ISTR is indeed the regulator. (Just checked again - oh no it isn't, it's the activated charcoal filter flap open. Would this affect the cooling of the air?)

The refrigerant pressure is 10 bar, which is a touch low, but acceptable, so it would seem the compressor is not engaging. Also, the revs do not change when using the Econ button, which would tend to confirm this diagnosis. Does the regulator also control the compressor engagement, does anyone know?

E55BOF