I noticed this morning when I started the car that the snowflake -- usually on if it's below 37F -- was off. The dash thermometer read 10F (I'm in Boston), but the light stayed off for the duration and also failed to come on during my next trip. The temperature reading never got above 12F.

Is there ever a time when the snowflake stays off in cold temperatures, or is mine broken? If so, are there any guesses as to probable cause?

Thanks.

Not sure if the numbers are still the same but when this system was introduced in the USA in 1993, the cut points were 36 deg and 17 deg. Any warmer than 36 or lower than 17 and it won't come on. It's to warn of imenent road icing, and by the time it gets down to 17, you know it's cold. Sounds like it's working properly. NEVER seen one fail, except if the clock/trip computer went dead.

> ... and by the time it gets down to 17, you

> know it's cold. Sounds like it's working properly...

I suppose if it's above 17F, you still don't have a clue that it's cold, right?

The manual says "The light indicates temperatures when road icing may occur". The range on '98 S70 is 23-36 dF (-5 - +2 dC).

This light warns you of the possibility of losing traction. No more, no less.

Vadim.

> This light warns you of the possibility of losing traction. No more,

> no less.

Do you really think that ice isn't slippery below 17 F . I was going to ignor your silly post but now I will explain to you the probable reasoning behind the lights range. The upper limit of 36 is because you may not be aware that it is approaching the freezing point. Also when it is near freezing the snow on the side of the road will melt and make a road which was cleared , now a road covered with ice. When the temp is below 23 most of the ice or snow will stay frozen and not spread into the road. Also if the light was on all the time then you would not pay attention to the light. If you lived in an area which experienced winter then you might be able to figure that out.

I can see your ego has been hurt... Poor baby...

> Do you really think that ice isn't slippery below 17 F.

I never said that. Learn to read and comprehend.

Get yourself a decent book on popular physics and read it in your spare time. Pay specific attention at:

a) aggregate states

b) friction

17F isn't any different than, say, -50F. What matters is that under 17F there's no water (in its liquid state) between your road surface and the tires, unlike near-freezing temperatures (which, BTW, is the conclusion you came to further in your post)

>If you lived in an area which

> experienced winter then you might be able to figure that out.

I used to live in an area covered by snow from early November to mid-April, so I think I qualify.... :)

------

On another note, let's stop this fight. Think whatever you fancy, I couldn't care less.

My warning light comes on with the temp drops to 36 degrees F. It stays illuminated until the temp drops to about 25 degrees or below when is goes out. This happens every morning as I pull it out of a garage that usually stays about 45 degrees.

Marc,

The "snowflake" only lights when the temp is around 32F/0C. It is my understanding that is a freeze/transistion point warning,the slippery danger of both ice and water. So off when "very cold." I guess the the folks at Volvo think we'll know if it's for sure freezen, you betcha.

> cold." I guess the the folks at Volvo think we'll know if it's

> for sure freezen, you betcha.

No, it's because the traction improves (not as 'slippery') as it gets colder past 25F.

Cheers,

Vadim.

> No, it's because the traction improves (not as 'slippery') as it gets

> colder past 25F.

My ice is just as slippery at -15 F and 30F. The light is to warn you of the potental of running into slippery conditions and they do assume that you are smart enough to realize whan it is well below freezing.

> My ice is just as slippery at -15 F and 30F. The light is to warn you

> of the potental of running into slippery conditions and they do ...

You are mistaken. Your ice, although much more slippery than asphalt, is *not* as slippery at 15F as it is at 32F. At near-freezing (or near-melting) temperatures the friction coefficient is much less because there is a layer of lubrication (water) between two surfaces. At lower temperatures there's no lubrication. That's why 'cold' ice is less slippery than 'warm' ice.

If you ever lived in a cold area where temeratures drop well below 32F, you would know that.

Cheers,

Vadim.