A tip to check the CCU sampling fan at the back of the unit, without taking it out of the dash.

Use a small piece of paper, a little bigger than a stamp. With the unit running, place the paper over the vent hole. There should be enough air flow to suck the paper to the unit, and keep it there!

If the paper does not hold firm, the fan is not working, or the passage is clogged up. (My case) After a cleaning, the paper is sucked tight to the vent hole! Yep, I did follow a DIY to help get it cleaned.

 

Which DIY did you follow to clean it?

 

The multi talented Tore!

Here is a link to his work:
www.ccu.tore.bergvill.com