Hi,

BMW E87 2.0D 143 HP. I have a problem with the air conditioning. Coolant is. Tight air conditioning. When the air conditioning is turned on, the compressor always turns on (the clutch is engaged), but the radiator fan does not always turn on. When the fan is off, the air conditioning does not cool. I've noticed that this problem occurs mostly when it's sunny and hot. When there is no sun, the air conditioning cools. What could be the reason?

Morning Przemyslaw

Welcome to the Forum

The Fan receives signal information from several sources "engine temp" "outside temp" " cabin settings" " AC gas pressure" a full diagnostic session will help. Make sure the system is fully charged an AC specialist or Garage will have a machine that checks for leaks before charging then if the problem persists get a diagnostic done.

All AC systems lose a little each year so over time will need recharging. Also if the AC isnt run regularly the seals can dry out allowing gas loss.

Dave

Ok. Thank you for the information. The air conditioning was refilled and checked for leaks a few days ago. it's ok. there was a problem during high heat, because then there was no cooling.

 

Przemyslaw

Get the Heater/AC control panel checked they are a possible fail point and an easy change. Does the fan run at all?

Dave

I checked the PWM signal that is fed to the fan. The compressor clutch always works when I press the AC button. The fan runs when the PWM signal changes. But not always the PWM signal changes when the air conditioning is turned on. It also does not always change when I raise the temperature, for example, to 28 degrees and reduce it to 17 degrees. Then the fan won't work.

 

Przemyslaw

Hi

Is the car cool when the AC is on ? The fan only runs to provide additional air flow through the condenser when required, standing traffic or high engine temp. 

So as I understand it if you raise cabin temp to 28 does the AC compressor trip out let it stabilise then reduce to 17 the AC compressor should run and cooling in the cabin begin, the fan should only run if temp/pressure in the condenser is high. As the fan only runs as required and you are seeing a change in PWM signal I am not sure you have an issue 

Dave

Ok, I check it.

 

Thank you