Defrosting the windshield

Maggie

If I recall, when I poke the Defrost button on the wheel, the Outside air is automatically selected.

Make sure you clear the ice/snow away from the HVAC port under the windshield, or it could suck in snow.

jay

 

Maggie

I'm stuck in the office right now, but I'm fairly certain when you press the Defrost button on the steering wheel, the car selects outside air.

It would make more sense - on the surface - to heat up inside air than to take cold outside air and try to heat that up. Especially in an extreme example, say at -40.

Cold outside air has very low humidity, and that's important to keeping the windshield and other interior glass surfaces free of fog/ice. If you recirculate inside air, and heat it, the interior glass will quickly fog then ice up.

jay

 

Maggie:

If I recall, the fan speed will revert to the manual or Auto setting, depending on what mode you preselected. No, the fan speed cannot be set from the wheel, unless I never learned how to. On the lower right spoke are buttons for things like rear defrost and front defrost, pressing the front defrost button engages the windshield defroster.

In cold weather, it's best to preselect outside air, especially in temps below freezing.

jay

 

You don't need to adjust temperature or fan. Just press the "front defrost" button for extreme situations, and select the defrost vent for lesser, or ongoing, situations.

Like jayman said, the system uses low-humidity outside air for defrosting. All cars do.

In the winter I select the defrost "vent" setting, and should I ever need extreme help, I punch the big defrost button on the steering wheel. That's it.

 

Semantics. Okay, "In the winter I select the defogger "vent" setting, and should I ever need extreme help, I punch the big defrost button on the steering wheel. That's it."

Don't know why you had trouble this morning.

 

Maggie it appears you have changed your avitar? it is hysterical! ...or am i jelous i can't fwap someone on their noggin and have them fall into ice cold water? Now that i mention it some posters here could use same treatment!! to answer your last question...rear windshield is defrosted by heated wires imbedded in the glass, front is by warm air blowing over the glass which seeems to take longer. so the question is why can't they imbed heat wires in the front windshield?

 

It's the same defrost as is on a standard car -- that is, hot air being blown onto the window. So, it should start at the bottom of the window just like a normal car.

 

Is ther a difference? or do they just use two words for the same function?

When I'm in "auto a/c" and push the defrost (front) button it changes fan speed and dumps all the air out up by the windshield and side windows; if the temprature is above some preset temp (around 35 or 40 I think) it turns on the air conditioning before it heats the air for the defrosters/defoggers. If I have a manual fan speed selected turning on the defroster won't change that it just rerouts the air to the defroster outlets. If I have the air conditioner manually turned off I am not sure it will turn it on, I don't think so. Whatever manual settings I have selected (i.e. fan speed or air outlet) will be restored when I push the defroster button off.

The rear defogger doesn't do any thing to the airflow, it just applies power to the heating elements in the rear window and side mirrors.

This is what I think is happening based on what I have observed and what I read in the owners manual. If I'm wrong please let me know.

edit: The tech where I bought my car said the dots were a sun shade and had no other purpose.

P.S I spent some time in the Antarctic and got to observe a lot of penguins, do you know why they play this little game and try to push each other into the water?

 

Maggie

If you mean the dots around the rear view mirror, it appears to be some sort of sunshade material. Otherwise you have to wait for hot air to come out before any defogging/defrosting will occur. When cold that can be a long time, especially since the Prius motor produces far less waste heat than conventional motors.

Some cars did have front windshields with electric defrost. I seem to recall Gm brand minivans in the late 1990's having this optional feature. It was almost impossible to see into the vehicle, if you met one it could be sailing down the road empty for all you'd know. From outside the windshield looked like reflective glass you see on office buildings.

A co-worker has a new Range Rover and the front windshield has electric defrosting wires. If you look closely you can see the thin wires, they are much thinner than the rear defrost wires.

I wish most cars offered electric front windshield defrost, especially in a climate that can dip to -40.

jay

 

Sometimes there is a seal waiting under the ice flo, the first one in get's eaten so nobody wants to be first. Sometimes it's tough to be a penguin.

One of our biologists told me that the Adelie Penguins actually can't tell the difference between males and females themselves. They use rocks to build their nests with (nothing else to use) and the boy penguin picks up a rock and drops it in front of another penguin, if that penguin picks it up and starts to build a nest he knows he chose a female if it ignores him he tries another one. That's what he (the biologist) said when I ask him why the penguins kept dropping rocks in front of me anyway.