Auto-on/off headlamps?

The sensor in my 2000 Intrigue didn't work very well so I'm glad Toyota did not put auto headlights in the Prius. If you want the headlights (& tail lights) on during the day then turn them on. The length of time the lights stay on after the car is turned off can be adjusted.

 

My Gen III has a light sensor on the dash. What is that used for?

 

The sensor on the passenger side of the dash is actually used for the climate control system. I'm not sure but it may be sensing IR rather than visible light.

 

No we don't have auto-on headlights, I had them in another car and never used them because they didn't work to well.

But the Prius lights are auto-off after a 30 second delay that starts when you open the driver's door with the lights on and the car off. The dealer can set the delay to 0 seconds so you can use them as DTRs. Some dealers do this free, others want to charge for it.

 

tangentally related anecdote: A friend of mine once picked me up from the bar (I had a bit too much to drink one night after work) and his 90's Lincoln Towncar had autoheadlights and they turned off when he stopped at a particular intersection at night.

The night he picked me up he got pulled over because his lights were off as he sat there. Then he got pulled out of the car to do the field sobriety test because the cop could smell alcohol. The booze was me. I was a bartender at a busy night club and was covered in booze and beer after a shift.

the cop said he 'seemed okay this time so I'll cut you loos e as a favor' and my guy started demanding a breathalyzer because he literally hadn't had a drop that day and got a bit ruffled at being lectured to for not only being sober but being a good guy and going out of his way to get a drunk friend home. They didn't breathalyze but the cop did apologize for implying that he was 'borderline'.

end barely related tangent

 

Using the headlight with auto-off isn't quite the same as having real daytime running lights. Specifically, DTRs run at much lower power than regular headlights, so you'll be setting up for increased power consumption and quicker replace rate...

 

"My" G3 is a company car. We're required to run lights-on, so the auto-on headlights aren't a big deal for me personally, but I LOVE them with my GM!! I also like the fact that GMs have real retained power, unswitched 12-v outlets, and a functional battery saver, but that's a side issue.

I don't think I've turned off my lights at the stalk switch in several months. I park the car, get out, lock the car (also required by my company) and the lights go out. If I don't lock the car, they'll eventually go out anyway, IIRC.
I'm very surprised that if I leave my map light on in my Toyota, it will burn until the 12-v battery goes Tango-Uniform....judging from posts that I've read. I haven't tried it myself.
It seems to me that the Aichi Iron works could have thought that one out a little more carefully, given the smallish (and hard to replace) 12-V battery, but there is a bright side. I think you could probably jump start (boot) this car with 9 "D" cell batteries! I know you can use a Dewalt 12-v power pack....

I thought I recall reading that the photocell in the copilot's dash area is the same photocell that's used in the Non-US spec cars for....automatic headlights. IIRC, the sensor is installed and prewired (the expensive part) but this system is not enabled in US spec cars.
Anybody know if this is true and/or why?
I've never read where this sensor has anything to do with HVAC. Why use an IR sensor, when a $.50 thermistor would work just as well??? If it isn't a photocell, why the grey cover?
Anybody out there know????

 

Reading the manual I saw there was a configurable setting to have the dashboard lights alter their brightness according to ambient light levels. Also not enabled by default. Don't have my manual here to check the details, but that could explain the sensor.

 

Come on Chief get qualified!

Maintenance manual in the Heating & Air Conditioning section page 6217 identifies it as a Solar Sensor, I don't know for sure if it is IR or not that was just a guess by me.

There is a logic diagram for the HVAC system on this site somewhere, we talked about it when the car first came out. I can't find it right now but if I run across it I'll post a link to it.

EDIT: Still haven't found the logic diagram but here is the HVAC wiring diagram. Check out page 6, there is a hint that the Solar Sensor is used for both the HVAC system and the auto headlights, (if equipped).

 

The Gen II Prius was available with auto headlamps, but not in the US. In the US, many of the Prius had HID headlamps, and HIDs are poor candidates for automatic operation: they respond poorly to being turned off and on quickly, which can happen with automatic operation. On my Gen II you can see the spot on the dash for the automatic sensor.

For the Gen III I'm not sure why it isn't an option. None of the Gen IIIs have HIDs, so it can't be that. It may be marketing inertial from the Gen II.

Tom

 

I wonder if the dash sensor does anything at all on the US-spec. Gen III...

FYI, from page 207 of the manual

 

Yes it does, it helps the climate control system decide how much cooling is needed to arrive at the correct temperature. The climate control system uses pretty complex fuzzy logic and it needs to know how much sun light is coming through the windshield.

In cars with auto-on headlights it also decides when to turn the headlights on.

 

LOL!
Hey man!
I've only been on the boat for a year (21,000 miles)

On a real boat, they don't give you your fish in the "Welcome Aboard" package so that they can keep flying the silver dolphin flag!!! ---just sayin!

I'll buy the light dim sensor....with reluctance. The HVAC "solar sensor????!!!! C'mon!
You mean to tell me that the Aichi Iron works installs a daylight sensor for the HVAC system, but eschews automatic headlamps only on US-spec models?????
Whiskey Tango Foxtrot??!!

If there's a country that really needs help with the driving task, it's the good old USofA!!!!!!

Here's what I would do if I were KFAD.....
Install user-defeatable auto headlamps. This will allow for folks to use them if they desire, but also keep the Ron Paul hacks happy.

THIS actually makes more sense than anything else I've read....

 

Here is my take on it. Yes, it really is a solar sensor for the HVAC also used for auto on headlights if you are somewhere you can get them. If I can find the fuzzy logic diagram for the Climate Control system I'll post it. I think the HVAC system is standard for all Prius(us) everywhere they sell them. We may be the only country that doesn't get auto-on headlights at least as an option, I don't know why.

I agree with the rest of your post.

BTW I was a forward ET on fast attacks during the cold war, about a million years ago.

 

In Canada, daytime lights are standard and my 2010 also has an auto headlight setting that switches the full headlights on and off depending on ambient light.

I like it a lot. It works well and I leave it in Auto all the time.

We also get 3 door smart key in the Premium which is roughly the same as a III but before you get too jealous, compare the prices on each side of the border.

 

I haven't looked carefully at a Gen III, but the Gen II has two daylight sensors: one for the auto headlamps, and one for climate control. The climate control sensor is a little black hemisphere that heats up when subjected to sunlight. It helps the fuzzy logic control system that manages heating and cooling of the cabin. The thinking is that people get warmer when directly heated by the sun. When the little sensor gets hot, it is likely that the driver is also hot.

For the US versions of the Gen II the auto headlamp sensor is replaced with a blank. You can see where it goes, but we don't get the actual sensor.

Tom

 

That can't be right because many Lexus cars with HIDs have AUTO ON.

 

If I'm looking at it right the Gen3 HVAC wiring diagram (post #10 of this thread) indicates the Gen3 uses the same sensor for both. It's on page 6 of the diagram.

 

I think it is true, my BMW had HIDs and Auto on/off. According to the forums quite a few people who used the Auto feature with their HIDs had trouble with ballasts and igniters, both more expensive than bulbs. They don't like being turned on and off a lot. That's one of the reasons I never used the Auto on/off feature in that car.

It could also be that Lexus uses better quality electrical parts, a lot of the electrical stuff BMW used was just junk compared to Japanese and American products.

Fortunately halogen & LED lights don't have that problem. So why don't the U.S. Toyotas have Auto on/off headlights? Could it have something to do with CAFE standards? The car might get an extra tenth of a MPG with the headlights off and for CAFE computations all those tenths add up.