What Should I Expect from the Cabin Heater

[gmcmurry]

OK -- I live in Southern California so I hardly ever need heat.

We are having a nice rain today so I turned up the temperature to 74 to see how the heater worked.

Not much in the manual explaining how to turn the heater on, so I am guessing I just turn the temp up.

It worked but it didn't seem to get very hot. However, I only went for a short drive.

I know how it functions so I am wondering... How long does it take to warm up and how hot should it get?

Most of what I read talks about heater failure. I am guessing if it had failed, it wouldn't heat up at all.

Greg

 

[miimura]

If you use Auto Normal mode, not ECO LO or ECO HI, and set it at least 10 degrees above ambient, it should get quite warm within a minute or two.

 

[gmcmurry]

Thank you for the suggestion...

I did discover that making sure I hit AC Off really helps. I never thought about the ECO mode.

Greg

 

[asavage]

Here, it's fairly slow to produce heat. It has to heat water, then circulate it to the OEM heater core. I don't feel discernable heat for about 2.5 minutes.

Unfortunately, this is one of those systems where asking for a higher temperature really does get you hotter air: move the temperature higher and you get hotter air (for a while). It modulates the output temperature, though poorly, IME.

 

[ZoNiE]

It delivers heat faster than an ICE car on a cold day.

 

[asavage]

Something I forgot to mention earlier: like a lot of Toyotas, our RAV4EVs incorporate a Quick Heater (PTC/"resistance strip heater") in addition to the conventional water-fed heater core that's heated by the HV water heater that fails. The PTC heater is only 840W, but that's not nothing. It's a three-stage strip heater.

It's the same Quick Heater that was used in (some) 2008-2012 conventional RAV4s, part No. 87710-42040. I picked one up off eBay or somewhere, just to look at it.

I put together some info on these last April.


An observation: I normally run the HVAC in Normal mode, but a couple of weeks ago I had an unusual drive and weather conditions that led me to switch to Eco mode (can't recall if Eco Hi or Eco Low), and within twenty seconds I noticed a burnt dust smell. I wondered where that was coming from, and then I remembered the Quick Heater. I surmise that it possibly is not used in Eco mode(s) at the ambient temp ranges I drive, and when exercised for the first time in probably a year, some local dust got singed.

I don't know any of that to be factual, it's just a guess. I haven't delved into the online shop manual, other that to review a couple of diagrams; it's not all that important to me right now, as I'm not commuting these days.

Later various Toyota models seem to have dialled back to lesser-wattage PTC heaters, some with fewer stages.

Fuse locations for the three stages of the Quick Heater, from the owner's manual, pages 391/392:

 

[asavage]

2+ years later, I see that several image links did not survive the forum's migration from phpBB -> Xenforo, and the links themselves -- which used to be descriptive and on my own server -- have been transformed to gibberish, so I don't even know what the images represented, and therefore I can't repost them, though I still have them all.

The Wayback Machine doesn't seem to have it archived, either.

Such is info rot on the internet.

 

[bdunst]

Al - I checked your link above that is some info - and all the pics are there - not sure if thats whats missing here.
Is this used in conjunction with ethe other heater or just used as the heater in eco mode?

 

[asavage]

As an example of broken image links from my original post:



As to when the PTC heater is used . . . IDK. I've meant to build a breakout harness for the relays for the three stages and check when they're activated, but it just hasn't been all that important to me. If you discover the info, please post it.

Based on the clue that I had written, "owner's manual . . . 391/292", these are probably the two missing images that the phpBB->Xenforo forum upgrade FUBAR'd:

A couple of earlier broken images (probably):