Car defrosting on driveway, lesson learned

AC doesnt work below 5C as otherwise the condensation can freeze on the evaporator core and block cabin fresh airflow and ice may deform/break the fins.
 
As a heads up for BMW owners with "push button" start. If you start the car, then stop it. Take the key out it can be started again for IIRC up to 30 secs meaning with one set of keys you can start the engine, lock up and leave it running warming up... Design, or design flaw I don't know but it works on mine...
 
Googled what the A/C Compressor cycling switch does:

CLUTCH CYCLING SWITCH
Switch used to control evaporator core temperature either by system pressure or an electrical sensing bulb. Clutch cycling switch controls electrical current to the compressor clutch preventing the evaporator core from freezing during operation


The compressor will cycle for the following reasons:
Ambient temperature low, refrigerant pressure low as a result of low ambient temp.
Ambient temp high, cabin temp low, evaporator exchanges little cooling because cabin is already cool.
Ambient temp warm to high, fan set on low, same reason as #2.
Ambient temperature high, cabin temperature high, system charge low.
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http://autoacrepairs.com/cycleswitchinfo.htm
 
MatteH Oxford said:
No temperature sensor here

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So what about the Powertrain Control Module which has ultimate control over the compressor clutch solenoid? Does that not have a temperature sensor connected to it?
 
its one of those lessons that shouldn't need to be learnt,, a bit of common sense goes a long way

shame about the motor
 
Update: The police found the car, apparently it was dirty inside :S

It sucks that the person that did it probably lives in that estate, where they put nice new big houses next to ****box council houses and the rich/poor divide is incredibly noticeable, one long road seperates nice area from horrible area. Oh well, at least she won't be shelling out for a new car.
 
Ni-on all the cars I have driven (which is LOTS) the air has never worked at below 5c /end please.
 
[TW]Fox;20827161 said:
No you can't. Once you move the switch to windscreen you can't switch the AC off. It automatically illuminates the AC light to indicate it is using (or attempting to but with no effect if its really cold outside) the air conditioning.

Surely everyone with a Mk2 Mondeo knows this, we used to get people asking about it on a weekly basis when I was into Mondeos, people seem confused by it (Its the only car I've driven that does this, to be fair).
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Yes you can. that was on the later models with the electric motor control for the heater flap. My car is an early one with the cable control for the heater flap.
The aircon can be off independently of the demist setting on my vehicle because the direction switch for the airflow is not linked to the compressor.

Basically, it is like the system in the mk1.

The increased volume of air is due to the recirculation not working in the windscreen position, the flap switches to draw air from the outside. This is controlled by vacuum & has nothing to do with the green light or the a/c being on/off. The volume of air does not & cannot change in this position due to any other settings via the heater controls or the a/c being on or off.

Regardless of whatever position the heater controls are set to, the airflow always goes through the aircon evaporator. The part that makes the a/c 'work' and hence the cooling and dehumidifying of the air drawn through the evaporator is if the compressor is running or not, regardless of what that little green light is doing on the switch.
 
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Dogbreath said:
So what about thewhich has ultimate control over the compressor clutch solenoid? Does that not have a temperature sensor connected to it?
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Only for coolant & intake air temperature . This is separate from the a/c system & is to do with what map the ecu uses for ignition timing & the fuel injection.

The connection in the diagram shows the link from the pressure switch to the compressor, if the pressure is too high or too low the Powertrain Control Module (ECU) will earth the circuit here & this shuts the compressor off. This circuit isn't linked to a temperature sensor.
Jonnycoupe said:
AC doesnt work below 5C as otherwise the condensation can freeze on the evaporator core and block cabin fresh airflow and ice may deform/break the fins.
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Not if you've got warm air running over it from the heater matrix when the car has warmed up a bit & you've set the heater to wrk with warm air + a/c. Before you say 'the cars warmed up and the a/c will work now', my a/c compressor will still operate from stone cold .

If the compressor is on, the a/c is on.
 
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I'm on my second MK2 mondeo here. Can guarantee there is no way to put the fans on the screen without the aircon light coming on. Whether that means the aircon compresser and the like is actually working I have no idea, smells like it does at the moment (musty air from barely using it at the minute)

Wish my heated front windscreen still worked properly, I've got 2 lines right in my line of sight blocking the view and the left side doesn't thaw out at all. Still, better than nothing at all! Still find it baffling that only Fords have this :/
 
MatteH Oxford said:
Not if you've got warm air running over it from the heater matrix when the car has warmed up a bit & you've set the heater to wrk with warm air + a/c. Before you say 'the cars warmed up and the a/c will work now', my a/c compressor will still operate from stone cold .

If the compressor is on, the a/c is on.
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In light of this question....I've never seen a HVAC unit that has the airflow going through the heater matrix core first...... it kinda cancels the point of heating the air when the evaporator conditioning will drop the air temp below customer demand.

Hence the evaporator will always be first port of call after the pollen filter to dry the air then the matrix and main distribution system blend heat to match what the climate control system calibration is set to do.
 
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