I'm getting an intermittent electrical burning smell coming from the ACC but only when the compressor is switched on, I frequently run the car with compressor off but switch it on now and again to keep it in shape. I've had it on constantly for the past few weeks and every now again this electrical burning smell wafts in to the cabin but disappears after about 30 secs and might only happen every 2 or 3 days. I normally have it set to 22 or 23 degrees. Definitely doesent happen with compressor off, any ideas anyone?

As you may know the compressor is mechanical with a electronic clutch, they're usually very reliable if possible stick your head under the bonnet when you smell it to see if it's being drawn in from the engine bay. I would more lean towards a fault inside the cabin say heater fan resistor, the clutch does not use a huge amount of power so feel it's another connected item to the ventilation in general?

the Climate has a solid state device instead of a resistor - apparently..

try and locate the basic location before delving further.., as you say it may well be drawn in / carried by ducted air

Mercky said:

......but only when the compressor is switched on, I frequently run the car with compressor off but switch it on now and again to keep it in shape.

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The only way to keep it in shape is to leave it on permanently.

That's what it's designed to do.

ACC or manual AC should be left on. You can be warm or cold, or anything in between, but the air is "conditioned" ie dehumidified and clean.

We have a Clio, and the AC has been on since we first picked the car up brand new in April of 2001. It's never needed servicing or anything at all other than the cabin filter being changed every now and again.

As for your burning smell, I'd leave the ACC on and trace where the smell is coming from.

Regards,
Mick.

Mick F said:

The only way to keep it in shape is to leave it on permanently.

ACC or manual AC should be left on. You can be warm or cold, or anything in between, but the air is "conditioned" ie dehumidified and clean.

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You can leave it on all the time, but it will wear the compressor faster and it will use extra fuel - how much extra might just surprise you. Leaving it off for extended periods is unwise and can cause premature seal failure, but leaving it on permanently isn't necessary.

Mick F said:

That's what it's designed to do.

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It's designed to be turned on when it's needed to cool and/or dehumidify the cabin, (or for at least half an hour weekly if you don't need to do either, which is almost never in the UK!). The manufacturer even provides a big hint that this is the way it's intended to be used, by fitting an on/off switch.

And it's probably best to leave it off once the outside temperature falls below about 4C (many systems will do this automatically anyway), since (1) there's not much moisture left in the air to dehumidify and (2) any that there is is likely to form as ice on the evaporator; it then all melts at once when you park up & might overflow the drain and drip water into the cabin. It's a common cause of wet carpets in winter.

But I'd agree that leaving it off for an extended period can cause problems, and it's probably best left on when temperatures are around 10C-15C with high humidity (which it has been in Dorset recently).

This is one of those systems where intelligent use of the switch beats having a rigid policy.

30 years of Honda's all had ac and I never turned it off!! Never had an issue other than recharging it every now and again, ok I did have a compressor seize but 1 in 30+ years is not bad and my dad has had ac for, ! 46 years and no issues just DON'T turn it off!

jrkitching said:

You can leave it on all the time, but it will wear the compressor faster and it will use extra fuel - how much extra might just surprise you.

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Wear the compressor?
How long do you want it to last?
Our Clio is rapidly coming up to 100,000miles and the compressor runs all the time that the engine runs.

Extra fuel?
We've had this discussion before. I prefer a dry, clean-smelling, comfortable car.
If the weather is hot, AC is good.
If the weather is damp, AC is good.
If the weather is cold and damp and dreary and wet .............. like it seems to have been since October last year .............. AC is good.

I cannot envisage using a car without it and I'm prepared to put the (small amount) fuel in.

Regards,
Mick.

I'll leave it on full time for the next few weeks and see if it gets worse, better or disappears altogether! Personally I'm not a huge fan of AC and bar it's handy demisting abilities I dont consider it really necessary in this part of the world but that's just me! In the summer if its hot I open a window and/or the electric sunroof, I prefer fresh air and there's little point running AC with them open. Re MPG, it's hard to tell but at an estimate I'd say it drops about 2 mpg with it on. I do like the ACC though in the sense that even with the compressor off, it will automatically control and vary temp and fan speed as necessary which is useful in winter.

Windows should be closed with ac,,,, hot summers day, stuck in traffic, stress, other idiots, cool car-worth every penny ? yes mpg drops but its worth it.