It's no better with the black switch. It's still impossible to see

g8rpi said:

Yeah,
I'm going to drop out of this now. I'm just a dumb chartered engineer who has been working with heat pumps on and off for over 30 years, what do I know.

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You don't seem to know how and AirCon in a modern car works.

My quote was regarding a Fiat 500.

Mick F said:

I will quote/paraphrase ..........

The cooling system works in the same way as a domestic refrigerator.
.............. the gas loses heat and becomes a liquid. The liquid passes through and expansion valve to an evaporator, where it changes from liquid under high pressure to a gas under low pressure. This change is accompanied by a drop in temperature, which cools the evaporator. The cycle repeats ............

Air blown through the evaporator passes to the air distribution unit, where it is mixed with hot air blown through the heater radiator to achieve the desired temperature.

The heating side of the system works in the same way as models without air conditioning.

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If my statement is wrong, I suggest you tell Fiat.
Mick.

If the switch has a standard T5 panel light bulb you can get a 2w version vs 1w or if it's a led change it for a high brightness version though this may require quite some work for such a small gain?
One of my very early Accords had a bright ac light great during the day but far too bright at night, the next series of car had a dimmer connected to the side lights.

I'd agree the telltale is far too hard to see. It's much too easy to leave the A/C on without realising it.

Perhaps it should be replaced with a button like this, which lights up brightly when pressed?

John202020 said:

If the switch has a standard T5 panel light bulb you can get a 2w version vs 1w or if it's a led change it for a high brightness version though this may require quite some work for such a small gain?

One of my very early Accords had a bright ac light great during the day but far too bright at night, the next series of car had a dimmer connected to the side lights.

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I believe fiat use a little LED, they deliberately spec a low output device to get the day and night balance, you could easily find and install a brighter LED but most of the commercially available LEDs you'll find on eBay and alike will be far, far too bright for this purpose and flood the dash area with intrusive light at night time.

When I've had these fiat switches apart in the past there is very little room to be able to tailor any sort of resistor to try and bring the brightness down.

Funnily enough, when we had a Mercedes A class, the A/C warning light came on when you switched the A/C off. The salesman explained during the handover that the system was designed to be on all of the time, hence the warning when you switched it off. This was confirmed in the handbook. This, combined with my own mpg tests and advice from A/C specialists, is why I always leave mine on. I also prefer the "feel" of the dehumidified air. But each to their own, everyone should be able to choose what to do with that switch!

A lot of cars have a Red Aircon light which I think may show better in the daylight than the green on the fiat 500 A dob of paint comes to mind !!!!!!