Hello, i have a 2017 ford focus diesel - there has been an increasing smell of what seems nail polish - what could it be. There is no lights on the dash board and is running well thanks

Air con system probably needs decontaminating.  This acrid smell comes from mould & bacteria growing on the damp AC evaporator.

3 minutes ago, TomsFocus said:

Air con system probably needs decontaminating.  This acrid smell comes from mould & bacteria growing on the damp AC evaporator.

i did spray 2 cans of detol as per a Youtube video - did not do anything. 

3 minutes ago, mrnody91 said:

i did spray 2 cans of detol as per a Youtube video - did not do anything. 

That doesn't surprise me.  I've tried loads of DIY techniques that aren't effective. 

Really need a foam cleaner to coat the whole evaporator for a few minutes.  The mist sprays just waft straight past.

Wurth cleaner isn't cheap but gives the best results.

5 minutes ago, TomsFocus said:

That doesn't surprise me.  I've tried loads of DIY techniques that aren't effective. 

Really need a foam cleaner to coat the whole evaporator for a few minutes.  The mist sprays just waft straight past.

Wurth cleaner isn't cheap but gives the best results.

i have booked a free aircon check at halfords 

8 minutes ago, mrnody91 said:

i have booked a free aircon check at halfords 

That won't help.  They'll just check the gas level and the temperature coming from the vents.

Need to book an air con clean to remove the smell. 

Remove the Cabin Filter before you do any cleaning, as it may still be the original. After cleaning, fit a new Activated Carbon Pollen Filter, not just a paper one.

Hopefully you don’t have a AC gas leak in the evaporator causing the smell. Chemical type smells from the vents can be caused by a leaking evaporator.