Climate control blower R129

[truck71]

Noticed something odd about the blower on the climate control. When the car is first started the fan will blow as hard as I ask it according to the LCD display on the centre console. After about 30 minutes the fan dies. The temperature of the air coming from the vents is in line with what I've set it but no blow. Any ideas?

[Momentum124]

I don't know if it is quite the same as my 1993 e-class, which does not have a digital setting, but once the climate control reaches the desired temperature the fan slows down. If you set the temperature a couple of degrees lower once the fan has stopped does it kick in again?

[truck71]

Not sure, I'll need to spend a bit of time experimenting. One thing I have noticed is it starts blowing again once in slow traffic. It's the lack of response to manual intervention that's puzzling.

It's going to be the daily driver next week so should suss the patterns.

[r129sl]

If the fan is blowing but no air is coming out of the vents, then it is likely a defective evaporator temperature sensor. This causes the evaporator to ice up so no air can get through.

[truck71]

I don't think it's that, the fan isn't blowing at all after about 30 mins running. It also does it when the temperature is set high. Odd one.

[truck71]

And today with the climate control set to 18 degrees it started blowing cold vapour through the vents- looked pretty cool but I doubt it's supposed to do it!

Curiouser and curiouser.

[truck71]

r129sl said:

If the fan is blowing but no air is coming out of the vents, then it is likely a defective evaporator temperature sensor. This causes the evaporator to ice up so no air can get through.

Having spent this week in the car I think you maybe right, the fan appears to be running but no air coming through. Part ordered, do you know which side under the dash it's located? All the instructions I can find on line are for left hand drive models..

[r129sl]

I am pretty sure it is under the left side, same as on a LHD car. The carpet under-dash panels are very easy to remove and replace: this is where the quality of design and build really starts to show.

[truck71]

r129sl said:

I am pretty sure it is under the left side, same as on a LHD car. The carpet under-dash panels are very easy to remove and replace: this is where the quality of design and build really starts to show.

Thanks. I have to agree, I've just sold a 10 month old Porsche 981 which has led to the Merc being the daily driver. The depth of engineering quality in the Merc is something else, interior materials, switchgear, the seat release levers- miles better than the new Porsche. Sure, it's got 17 years worth of wear and tear which leads to some squeaks and minor rattles but nothing too bad. Putting the hard top on has reduced the scuttle shake over very poor surfaces but on most A roads even without it the body control is impressive. I took my first look inside the sill covers over the weekend, heavy metal or what.