Ford Ka - Air Conditioning Problem, Fan Doesn't Start | Technical matters | Back Room Forum

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Tue 30 Jun 2020 12:26

Ford Ka - Air Conditioning Problem, Fan Doesn't Start - moward

Hi Folks, been a long time visitor to these forums but never directly taken part until now. I have a bit of a conundrum that hopefully someone here on the backroom will be able to help me out with.

I am having a problem with the air conditioning on my mums car, a 2009 Ford Ka Zetec (the one based on the Fiat 500). My initial suspicion was that the gas was simply low so I topped it up using a cylinder that I already had. The compressor clicked into life and appears to be running as normal. The pipe on the compressor outlet is hot to the touch, the return should be cold but isn’t.

At this point I noticed that the radiator fan was not turning on, (I think it is supposed to turn on at low speed with the ac). I checked the resistor found on the upper RH corner of the radiator and found that it was corroded and had detached completely.

I could not find a Ford specific part so I ordered a Fiat compatible pattern part. I’ve included a link to the manufactures website datasheet below (no doubt someone can confirm I’ve bought the wrong one ??).

https://ecom.eraspares.com/ec/newprint.asp?IdComunanza=15882

Unfortunately after fitting the new resistor pack, the low speed fan still doesn’t come on. The high speed fan works as normal when the car is left idling for some time.

Taking the car for a test drive, I noticed that the air coming into the car cools down when on the move. Also of note was that the whooshing/gushing noise that could be heard down low in the cabin (evaporator/expansion valve?) quietened down also.

Could the problem simply be that I still don’t have enough gas in the system and that I need to have it recharged professionally, or is the low speed radiator fan a separate issue by itself?

Many thanks in advance for any assistance that you can provide.

Regards,

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Tue 30 Jun 2020 13:21

Ford Ka - Air Conditioning Problem, Fan Doesn't Start - elekie&a/c doctor

The slow speed fan resistor is a common failure on this model and the 500 . It cannot be bought separately from main dealer . Comes with the fan unit . I’ve fitted these aftermarket resistors with no problem. The slow speed fan not operating does not prevent the ac working . All it means is that the fan cycles on high speed only . I would think the system needs to be recharged with the correct amount of gas r134a . These fill it up quick diy gas fill kits are very often not the correct gas . Check the label on the canister. There still may be a problem with the low speed fan circuit. Could be relay ( in engine fuse box) or wiring .

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Tue 30 Jun 2020 13:51

Ford Ka - Air Conditioning Problem, Fan Doesn't Start - moward

Hi Elekie, many thanks for your quick reply. Sounds typical of a main dealer to try and upsell and entire fan assembly rather than a simple resistor pack. No wonder I couldn’t trust them to look after my goldfish, let alone my cars.

Yes unfortunately by using a diy topup, I cannot be sure exactly how much gas is inside the system. The bottle is labelled as R134a, it was in an STP branded cylinder sold in Halfords. I did notice when monitoring the pressure on the low pressure port, that it dropped dramatically as soon as the high speed fan kicked in (went from about 30 psi to < 10 psi).

I did check the fuses in the engine compartment, and I swapped some of the relays around (on the premise that they couldn’t all be faulty) as I didn’t have a multimeter handy.

Is it feasible that whilst there is enough gas in the system to start the compressor, the output from the compressor isn’t hot enough to kick start the low speed fan? Hence more gas needed?

Thanks again,

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Tue 30 Jun 2020 18:12

Ford Ka - Air Conditioning Problem, Fan Doesn't Start - elekie&a/c doctor

The quantity of gas in the system is critical. Too much or too little will make the system not function correctly . By adding one of those quick fill canisters, you have no idea how much gas is in the system . Also , for the ac system to work efficiently, it needs to be evacuated to remove any air and moisture . The fan circuit works by monitoring pressure in the system .

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Wed 1 Jul 2020 09:02

Ford Ka - Air Conditioning Problem, Fan Doesn't Start - Railroad.

You're playing with fire. Air conditioning system repairs are not DIY jobs. Do yourself a favour and go to an expert before you do some real damage. There are plenty of them about.

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Wed 1 Jul 2020 12:42

Ford Ka - Air Conditioning Problem, Fan Doesn't Start - moward

Technically I’m playing with refrigerant, but I get your point :-)

My aim of adding some gas was to try and kick start the compressor to try and rule out any fault with it. It did click back into life, so I at least know that the clutch and pressure switches are likely ok. I’m not attempting any other repair on it.

Normally with the compressor running, the system does at least go somewhat cold (my experience in other vehicles I’ve owned in the past), but not on this car it seems. Which is why I wondered if the low speed fan not running was part of the problem.

The advice given above suggests that the operation of the fan should not prevent the ac working (air flow when on the move should be enough to cool the condenser), hence the likely problem is that the gas quantity in the system is incorrect (I suspect it’s still too low).

Whilst I may be an expert in FEA and stressing/sizing of aircraft structures, my knowledge in air conditioning systems is more rudimentary (unfortunate really as only one of these industries seems to have a future at present), therefore I will take the car to have it re-gassed properly before carrying out any further work.

I will update the thread with the (un)successful outcome once I’ve done this.

Many thanks once again to all for your help

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Wed 1 Jul 2020 13:00

Ford Ka - Air Conditioning Problem, Fan Doesn't Start - elekie&a/c doctor

For a better understanding of how ac works , take a look at joule- kelvin effect

Edited by elekie&a/c doctor on 01/07/2020 at 13:02

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Wed 1 Jul 2020 13:28

Ford Ka - Air Conditioning Problem, Fan Doesn't Start - Railroad.

Playing with fire is an expression. Air conditioning systems require periodic servicing. They are not maintenance free. The system will not work if it's got moisture in it even if the refrigerant pressure is correct. As I said before you would be best seeking an expert who has the equipment to evacuate the refrigerant, vacuum the system for a minimum of 20 minutes and then recharge it correctly. If yours is not working correctly it's probably long overdue a service. Checking to see if the fan works, and the compressor works is pretty pointless unless the system is free of moisture and correctly charged. Not doing so will only lead you up the garden path. What you can do is make sure the condenser fins aren't blocked with dust and dirt. Other than that there's not much you can do with any certainty.

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Wed 1 Jul 2020 13:37

Ford Ka - Air Conditioning Problem, Fan Doesn't Start - Railroad.

Add to that it's an 11 year old car. The receiver drier is probably in need of replacement too if you want a system that's going to work properly. They can only absorb so much moisture, and eventually need replacing because no amount of vacuuming can effectively remove it all.

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Wed 1 Jul 2020 14:09

Ford Ka - Air Conditioning Problem, Fan Doesn't Start - moward

Hi Railroad, I’m well aware of the expression playing with fire, my response was a little bit “tongue in cheek” (to quote another), hence the smiley. Humour doesn’t come across well in a typed format regrettably.

I agree with everything that you have said above, there’s no getting away from the fact that’s its an old car with old bits, bought as a simple runaround for my mum last year. I distinctly remember the AC working at the time when I test drove it so I am hopeful that its current predicament isn’t terminal and that its just a slow gas leakage over time due to lack of use.

I fully intend to take it to a garage with the correct equipment to evacuate the refrigerant and pressure test the system, hopefully at the end of this week. I’m realistic enough not to expect ‘as new’ performance, but even some cooling ability, if only to stop the windows fogging up, would be handy.

Good point about the condenser fins, I will have a go at clearing it out with my compressor (when the rain eventually decides to clear off here).

Many thanks for taking the time to reply.

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Wed 1 Jul 2020 15:35

Ford Ka - Air Conditioning Problem, Fan Doesn't Start - Railroad.

I agree with everything that you have said above, there’s no getting away from the fact that’s its an old car with old bits, bought as a simple runaround for my mum last year. I distinctly remember the AC working at the time when I test drove it so I am hopeful that its current predicament isn’t terminal and that its just a slow gas leakage over time due to lack of use.

And vacuuming. That part of the service is essential and must not be skipped. The sytem must be held under vacuum for at least 20 minutes, not only to test for leaks but to remove moisture. Even a small amount of moisture in the system will adversely affect the performance.

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