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Discussion Starter #1
Hello All, First post and I'm in need of some help! 2008 Fortwo, a/c was working fine but then stopped cooling, had a look today and the compressor is kicking in but the cooling fan is not, ran it for a while, bit of hissing sound from evaporator, expected I guess because gas is going through instead of liquid as it's not being cooled, then fan did start either with engine temp or high a/c pressure? a/c started to cool, intermittent because compressor cycled on and off so shut it down, question is why isn't the fan coming on with the a/c, can anyone point me in the right direction. Thanks.
 

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If you press the AC button, and the recirculate button, the inside fan should go faster. outside the AC compressor should go on and stay on (engine running, ) and the radiator cooling fan should run. If the AC compressor cycles on and off, you probably have low R134a in the system and it needs recharging. Once it is full, it should run constant until the system is up to temperature (or down to temperature) and then it will only run when it is needed. It is common for the refrigerant to leak out a bit when it is not used say during colder winter months, and over the years, it can need additional refrigerant.

It is best done by someone trained in handling R134a refrigerant to make sure the system is not experiencing other problems.

I am assuming the smarts in England are similar to the smarts here in the colonies :)
 

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Discussion Starter #3
Thanks for reply, you could be right about it being low on gas but my main concern at the moment is that although the compressor is working the rad fan's not, as you say it should be on, if the compressor didn't run I could understand it, do you know if the fan is single speed or two speed, I ask because it did come on to cool the engine so is working. Thanks.
 

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The radiator fan is a single speed fan. My car was low on refrigerant and the fan did not come on. As soon as I refilled the refrigerant, the fan came on with the A/C. I believe it still came on with the radiator temp as I did not have problems with overheating.
 

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Discussion Starter #5
Well managed to get the a/c sorted (for the moment) it was low on gas, turns out the fan only operates when high side reaches a certain pressure, 220psi I think and if low on gas it won't get that high, this makes sense as when moving forward air is forced through the condenser keeping the gas cool and therefor the pressure low (ish) so the fan turns off, when you stop the pressure rises and the fan comes on, what confused me (easily done) is I also have a Rover 75 and the fan is on all the time when the a/c is going, however it's a two speed fan and the 220psi?? pressure switch operates the high speed, as my Smart is single speed this switch can be used to save power/fan use which is good, the Rover should do that but then the Smart is smarter!
 

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Yup, got a 97 Rover and I have had my share of electrical gremlins in that one!! When I charged the AC on my smart, as soon as the pressure was up on the high side, the radiator fan came on.
 
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