Winter and Heater (A/C)

[BuildCode]

Originally Posted by yaris2010RS

has anyone actually found evidence of this? lol. i've seen it around here but is it actually true? i find in my car, untill the little green COLD light (which i am not a great fan of) turns off i willl not get much of any heat

EDIT: and would we also not get a little bit of a toaster like smell. all electric heaters let off some sort of smell for the first little while

Not sure, I wondered the same thing after reading about the electric heater on YW.

Is the cold weather package different than the all weather package? I just looked at my window sticker, and my "all weather guard" package has: Larger window washer tank with low level warning indicator lamp, heavy-duty heater, heavy-duty starter and rear heater duct.

[Yaris Hilton]

That may be the source of the rumor, but a "heavy duty heater" isn't an electric heater.

[BuildCode]

Originally Posted by Yaris Hilton

That may be the source of the rumor, but a "heavy duty heater" isn't an electric heater.

That's what I had figured after going through a winter with no signs of electric heat. Is it a bigger heater core then?

[Yaris Hilton]

That's my understanding.

Someone with time on their hands and a Toyota parts catalog could prove it easily.

[IllusionX]

Originally Posted by yaris2010RS

has anyone actually found evidence of this? lol. i've seen it around here but is it actually true? i find in my car, untill the little green COLD light (which i am not a great fan of) turns off i willl not get much of any heat

EDIT: and would we also not get a little bit of a toaster like smell. all electric heaters let off some sort of smell for the first little while

Mine does not produce much heat either until the light turns off :( Anyhow, i don't think we'll ever find evidence of it until someone actually takes the car apart.

Someone needs to grab the complete repair manual from a toyota dealer. I'll try to remind myself to ask for the heater core assembly diagram see what shows in there....

[sbergman27]

Originally Posted by yaris2010RS

has anyone actually found evidence of this?

I'd been assuming that evidence existed. But... a quick search doesn't turn anything up. I've heard that it's a ceramic heater. (Makes sense.) But a search of the FSM PDFs for "ceramic" doesn't return anything relevant. Neither does a search for "heater". Then again, I'm finding that the the FSM is more concerned about the acceptable pulse-width of the signal from the wiper speed sensor than it is about... you know... things that are actually, physically important for the functioning of the car. Things made out of metal rather than silicon. Like pistons, brake rotors, and heater cores.

The utility of an auxiiary electric ceramic heater is dubious. If you look around at various highway travel stops (e.g. Love's) you can find 12v, 15 amp electric heaters that plug into the 12v outlet. They draw between 150 and 200 watts, and are fairly inexpensive. So you can easily judge for yourself. They put out a *barely* perceptible stream of sorta warm air. If the Cold Weather Package built-in version drew 50 amps(!), that would be about 700 watts at 14 volts and *might* make a slight difference. (And why are we still using 12v electrical systems in the year 2010, I wonder?)

-Steve

[Rick]

This isn't legal proof, but it's there if you have the 'All Weather Package'. The factory manuals (I have them) cover it extensively. I have seen that my Base Yaris with 'All Weather Package' has the special AC computer with the extra connector. It's additional power wiring for the PTC heater element. From a Yaris perspective it does draw a prodigious amount of current when active. It's only active when the heat is set to max, the blower fan is on, the engine coolant is < 150F, and ambient temps are below 50F. You can see it's effect on system voltage with a Scangauge.

Search for 'How does a PTC heater work?' and you'll stop expecting to smell it or overtly feel it. It just speeds up the warming. I can definitely tell it does that where I live.

[Yaris Hilton]

Cool! (Or warm, I guess.) Thanks for that info.

[sbergman27]

Originally Posted by Rick

It's additional power wiring for the PTC heater element.

Aha! "PTC" is the magic search term. I was searching for "ceramic" earlier. It appears that it has three settings and two associated fuses, a 30A and a 40A. The schematic they give makes it difficult to tell what's happening. But I think that it might have a setting to pull through both fuses simultaneously (two separate circuits in the unit) for a total (upper limit) of 70A. At 14V, that works out to nearly 1000W, which puts it in league with the low setting on most household ceramic heaters.

-Steve

[IllusionX]

you see.. i wasn't all that crazy about the electric heater...


i'm not sure how there is a sensor that reads cabin temperature, but the < 150F coolant makes sense..

[sbergman27]

Originally Posted by IllusionX

you see.. i wasn't all that crazy about the electric heater...

No. You were right. What's *really* crazy is that we're still on 12V systems... where such a thing might *seem* insane. 70 Amps? Yowee!

-Steve

[Snappy]

In the US, the All Weather Pkg cars have the ceramic auxilliary PTC (Positive Temperature Cooeficient) heater. When does it kick in?

From the AC section of the manual:

"When the PTC heater operating conditions are met
(engine at idling speed or faster, ambient temperature is
10°C (50°F) or less, engine coolant temperature is 65°C
(149°F) or less, and No. 3 heater control knob setting is
MAX HOT), turn the blower switch to the Lo setting."

Does my car have one? Look at the _AC_ _Amplifier_, a black box screwed under the main AC box behind the center console. (Put your head down by the pedals, look under the left side of the center console, pushing the carpet out of the way.) TWO connectors? You have the PTC heater. One? No you don't. All this info applies to 2007 spec US models, others I don't know.
See selected pix from the online manual.
(Sorry if it is clear as mud.)