Prime may start ICE in EV mode if Windshield Defogger switched on

Although we're pretty happy with the Prime, the window fogging is a frequent problem. It seems a shame to have to start up and run the gas engine just to clear the windshield.

We've just discovered that turning the climate control on in "auto" or "A/C" mode with the fan speed set to high will usually defog the windshield without starting the gas engine. The key here is to set the fan speed manually to force air flow without waiting for the heat-pump to ramp up.

The owner's manual says: "Fan speed is adjusted automatically according to the temperature setting and ambient conditions. Therefore the fan may stop ... until warm or cool air is ready to flow immediately after 'auto' is pressed."



This approach won't handle situations where you need a lot of de-fogging power fast, but it will do a reasonable job of clearing a cool windshield which is fogging up from ambient humidity within the cabin.

Observation: the climate control screen in the image above is very confusing. It provides choices for "auto" "fan off" and "A/C" and then a low-to-high fan adjustment with the word "auto". Toyota's engineers would do well to revisit the design of this portion of the user interface for future models.

 

on a related subject, let's say your're in your Prime at a ChargePoint station and there's no stores or restaurants nearby or open and you end up sitting in your car fogging up the windshield, I found that by putting my keyfob in a faraday "cage" pocket and turning on remote climate at maximum heat with both defrosters on the windshield clears up and it's reasonably warm inside, I have done this with limited success, sometimes the remote climate will work but most of the time in the two hours I was sitting in my car it didn't work, the left and right turn signal indicators on the dash would blink momentarily but most of the time only the rear defrost would be working, could be another bug (tag) @bwilson4web

 

Has anyone else tried an interior glass anti-fog spray for this issue? I applied RainX interior antifog spray to my interior front windshield 11/11/22. Ever since, my windshields have been fog free without the need for the defogger, AC or fan. It is a little tricky to avoid minor streaks and smudges when applying. Make sure the windshield is clean first and follow the instructions on the bottle. I still got a little bit of smudges/streaks, but not enough to be distracting for me or affect my visibility. Before applying this to my car, I applied it to my bathroom mirror. A couple weeks later, my wife cleaned the mirror and they still visible when coming out of a hot shower, even though I haven't reapplied the product. Here is a link to the product I used.