Seat warmer turns on automatically

I should add that the accelerator click point is meaningful only in ECON Mode. In NORMAL or SPORT Modes, the engine starts before the click point is reached.

 

I'm probably the only Clarity owner that hasn't known this from the beginning, but I just realized/discovered that the setting of Econ ON or Econ OFF maintains its last setting between driving sessions, so if I switch it OFF and never touch it again, it will apparently be always be OFF. I had assumed it defaulted back to the ON condition on every new driving session.

That explains to me why the Climate Control performance was so great when we first got the car, quickly cooling or heating the car after startup, whereas in recent months, it has been marginal. Econ had apparently been in the OFF setting for many months, initially, until I started playing around using the ON and OFF options.

 

BTW, the seat warmer only comes on on the drivers seat right? Not happening on the passenger seat.. I do have ECON mode on.

 

Yes its driver side only, and only if the conditions are right. I think it has to be pretty cold in the car for it to auto come on as it doesn't always do it for me. The car is apparently more efficient heating the seat than the whole cabin so it will do that to not have to put the heater on as high is my guess.

 

How would one know when the 12-volt is low?

 

You can’t, as far as I know. This seems to refer to when the car is not fully on. I interpreted this as meaning the common-sense advice “don’t use the seat heaters for very long without the car being on, it will drain the 12V battery fast if the main battery is not available to recharge it”.


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Is it even possible to use the seat heaters without the car being fully on? I haven't tried it, but I hope not.

While I buy into the idea expressed by others that the power used by the seat heaters is less than would be required by heating the whole cabin, I'm a bit skeptical of the suggestion that since the seat heaters draw power from the 12V battery, it won't drain the main battery. I would expect the main battery would have to be restoring the same amount of power to the 12 V battery while it is under the load of the heaters. Seems to me there really wouldn't be an net advantage, but maybe I don't fully understand it.

 

I agree—I don’t quite understand why they wrote that. The “may make it hard to start” implies the seat heats are running while the car is off, but I can’t quite figure out how one could do that. I just now tried the car in ACC mode, which is what I thought they meant (one press on the power button with foot off the brake) and seats did not come on. So that’s not it.


Maybe some lawyer thing. Certainly I’d expect that if the main battery is engaged it would hold the 12V system at 14V (and therefore charge the 12V battery and also supply the seat heaters’ power) through the dc-dc converter, in the usual manner, as you say.


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I run in ECON mode all the time. Lately I have had one bar lit automatically on the seat heater. The other day, I noticed that there were TWO bars lit on the indicator! Welcome to almost-winter in Canada!

I have been very impressed with how quickly the cabin heats (and in the summer, cooled) even in ECON mode. It actually gets too hot sometimes. I can't imagine needing more than that.

 

Actually, I found a way to run the seat heaters off the 12V battery alone. This is a bad idea to do, but I could see someone doing it by mistake. Perhaps that is what Honda is cautioning about in the owners manual.

For background: if keys are in the car and you push POWER without your foot on the brake, you enter ACC mode. This powers the radio, wipers, and a few other things.

If you push it again, without your foot on the brake, it enters what looks like a "full on" mode: dash engine-warning and battery-warning light turn on and stay on, and climate control, headlights, seat warmers, etc. all work. Of course it can't be driven, and a message that "to start car, foot on brake and push ON" appears. This would be the equivalent of ON/RUN in an older car with a key ignition. I will call it ON even though the car is not ready to drive.

Of course, if you have your foot on the brake and power the car, it skips all of these and enters READY TO DRIVE mode; the dashboard warning lights come on and then go off.

Voltage across the 12V battery terminals during each of these:
-OFF: 12.3 V
-ACC: 12.2 V
-ON: 12.2 V. Seat heater, headlights comes on. I can find 30A flowing in/out of the battery with a clamp on ammeter. Since the voltage starts to drop, I presume out.
-READY TO DRIVE: 14.4 V.

I interpret this as meaning: when in ON mode, all circuits are live but the main (traction, high-voltage) battery is not engaged. You can merrily drain the 12V battery to the point where car won't start. I could see someone waiting in the car at a cell phone lot, etc. doing this. Maybe someone in the passenger seat, car, keys still in car, getting cold waiting for the driver to return. This is a familiar situation from full-ICE cars, as well.

If you are in READY TO DRIVE mode, no worries: the high-voltage battery will support the seat heaters.

An obscure circumstance. I assume the ON mode exists primarily for maintenance on the car (where you might want most things powered up, but the high-voltage battery to NOT involved even if stepped down by way of the dc-dc- converter).

 

I'm trying to solve an issue I'm having with my driver's side seat heater roasting my backside on long trips. I *think* it could be related to being in ECON mode, but in my case, the seat heater comes on about halfway into my drive (sometimes in summer, it just did it in spring with 80F temps outside, often in winter, too), and there's never a lamp lit on the seat heater to indicate the seat heaters are on. But boy do I feel it, especially after a couple of hours.

Is that normal functioning for the Econ mode seat heater function? Does it just come on without lighting the lamp? I've tried to turn it off by cycling the seat heater switch, but it doesn't help, and turning the car off/on doesn't help, and after 2 hours or so, it REALLY starts to hurt. Like some kind of crazy endurance contest.

I confirmed it was the car (and not in my head) by simply turning the car off, and the seat cooled down just about immediately.

I took it in to the local Honda dealership a couple of months ago, and they took it for 3 days and washed the car, and said it was fine. (Because they couldn't find an error code, so obviously nothing was wrong with it.) They had no clue if it was working as intended. -_-

Any suggestions?

 

Doesn't happen to me.

 

That is not normal behavior

 

I kind of figured it might not be normal, but I wanted to make sure. Damn. Honda has been pretty useless about fixing it, too.

 

Sounds like a bad seat heater relay. It’s closing on its own or it’s stuck closed. Would make sense that it gets uncomfortable as it would be stuck fully on.

 

I'll go at it with Honda again then. Literally, their response was, "No error code, no problem." -_-

 

Start keeping track of the number of times you have asked them to fix it and then threaten them with the lemon law. That should get their attention.

 

Thanks for all the responses BTW. Yeah, I've kept an eye on the NC Lemon Law requirements, and we're not close yet. Needs another 12-13 days of failing to repair it for that to happen. I think if it's just the relay, I'll be back(side) in business.

 

It’s normal for the seat heater to come on if the system is calling for heat and the car is in ECO mode, but the indicator lights should show it. And of course the system should not be calling for heat when the temp is 80s.

-You can prove it to your own satisfaction by pulling the fuse for the seat heaters. Behavior should stop. I’d consider doing this to make your case.

-proving it to Honda is trickier. I guess you need to keep bugging them. A picture of the seat with an infrared camera showing the coils lit up would do it, but IR cameras are a couple of hundred even as smartphone attachments.

Relay idea is sort of plausible, but when a normally-open relay sticks in the closed (conducting) position, it’s usually permanent failure in that position. Odd that this would happen partway through long trips.