Mondeo 3. A/C is not working properly

[GregoH]

Hello,

My A/C is blowing warm air(27 Celsius) when it is set to 16-20 degrees Celsius.

When I set it to LO - it works properly and blows cold air(3-4 Celsius).

All measurements were taken directly from air vent.

Tried automatic setup, but this did not solve the problem.

What can cause this problem? Can low refrigerant level cause it?

Thank you!

 

[nicam49]

It could be that the cabin sensor is clogged up. Needs removing and vacuuming out, probably, or you could try putting the vac nozzle against the vent and hoping to suck up any fluff,to save you having to dismantle anything to gain access

[GregoH]

2 hours ago, nicam49 said:

It could be that the cabin sensor is clogged up. Needs removing and vacuuming out, probably, or you could try putting the vac nozzle against the vent and hoping to suck up any fluff,to save you having to dismantle anything to gain access

So, air doesn't blow directly on this sensor, because there is a lot of fluff in the vent, and sensor tells A/C that it is very cold inside the car. Sounds reasonable.

I will try to vacuum it. I noticed that A/C doesn't blow at all on my left foot. 

Now it makes sense. Thank you!

P.S. Does it looks like the one in the photo?

[nicam49]

That's the one. It's got a little fan inside it. 

[GregoH]

There was no fluff and fan was working, but I cleaned it anyway. Now A/C is working correctly 50/50. I guess my sensor has some problems with connection, probably because of old wires.

It was some white grease on the connector pins. Should it be there? Or it may only cause the problem?

[GregoH]

Well,

Same problem with new sensor.

[nicam49]

Have you renewed the cabin filter ever? If you can't remember, then I'd recommend changing that next. 

[GregoH]

2 hours ago, nicam49 said:

Have you renewed the cabin filter ever? If you can't remember, then I'd recommend changing that next. 

Nope. I bought the car 3 month ago.

Everything I know - oil and oil filter was changed last summer.

So, I'm planning to change all the filters and fluids in June.

[nicam49]

Everyone neglects the pollen/cabin filter. So worth a punt changing. The long life ones have carbon or charcoal in them. 

[GregoH]

Well, now A/C is blowing only cold air in any mode. I did nothing. The only difference that it is warmer outside than it was before.

[nicam49]

So you've now got no heat from the heater? So the symptoms have changed since you worked on the cabin sensor...? If 'yes', then recheck the sensor is connected properly after you removed it, OR did you replace it with a different one...? If YES, then put the original one back and see what happens. 

[GregoH]

On 5/25/2020 at 8:49 PM, nicam49 said:

So you've now got no heat from the heater? So the symptoms have changed since you worked on the cabin sensor...? If 'yes', then recheck the sensor is connected properly after you removed it, OR did you replace it with a different one...? If YES, then put the original one back and see what happens. 

Well, sometimes it is working correctly, sometimes it blows hot air and sometimes really cold. Both sensors - same results. Sensor fan is working. 

AC reset helps every time.

I suppose there was problem in air mixing control. Checked air temp flap motor - it is working.

[nicam49]

Did you change the pollen filter or do you know that it has been renewed recently? 

[GregoH]

On 5/20/2020 at 2:58 PM, nicam49 said:

Everyone neglects the pollen/cabin filter. So worth a punt changing. The long life ones have carbon or charcoal in them. 

It was it actually. Problem solved.

 

Thank you!

[nicam49]

16 hours ago, GregoH said:

It was it actually. Problem solved.

 

Thank you!

 

Wow! Thanks for the update👍sometimes the complicated-sounding problems are down to the simplest causes.