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Glove Box Light Stays On

Discussion in 'Gen 2 Prius Technical Discussion' started by prigene, Feb 23, 2011.

  1. prigene

    prigene New Member

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    When I have the headlights on the glovebox light is on - even if the glovebox door is closed. Is this a known problem of only my own problem?

    What's a likely cause and fix?

    Thanks,

    gene
     
  2. prigene

    prigene New Member

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    Oops, I meant to write:

    "Is this a known problem or only my own problem?"

    gene
     
  3. prigene

    prigene New Member

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    So as not to appear negligent, I must say that before I posted my question about the glovebox light I had tried the Search function and got no hits, so I posted. Then I saw the previous posts about the same topic, and I now have my answer.

    End of my post, question resolved, many thanks,

    gene
     
  4. qbee42

    qbee42 My other car is a boat

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    This is also posted in the wrong forum. It should be in the Gen II forum.

    Tom
     
  5. Rest

    Rest Active Member

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    I never understood why Toyota couldn't spring for a $2 switch to turn this light off when the glove box lid is closed. Wasting power, no matter how little, seems to go against what the Prius is all about.
     
  6. jdenenberg

    jdenenberg EE Professor

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    It's only on when the lights are on. It is less power than the continuous power drain when your Prius is off.

    JeffD
     
  7. qbee42

    qbee42 My other car is a boat

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    Furthermore, that $2 switch adds weight, additional wiring, and another point of failure. It doesn't make sense, considering the tiny amount of power required to operate a single LED.

    Tom
     
  8. uart

    uart Senior Member

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    Yep mines the same. Don't worry about it. :)
     
  9. Rest

    Rest Active Member

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    It makes perfect sense because the added cost and weight is negligible compared to the power it would use, over the life of the car.

    The weight could have been reduced elsewhere in the vehicle, like the radio antenna, floor mats and owners manual size.

    The wiring would just take the place of the existing lines.

    And when's the last time anyone had a glove box light failure in a vehicle? I've only had a bulb go out once, back in 1977.


    And while yes this light is only when the headlights are on, some people keep their headlights on all the time. So their power drain would be even greater over the life of the car.
     
  10. Patrick Wong

    Patrick Wong DIY Enthusiast

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    BTW, the 2004 EWD shows a switch and bulb for the glove box (although I don't think this was actually implemented.) However, the 2006 EWD shows that this was replaced by an unswitched LED.

    How much power does a typical LED consume: 0.05W? This is really nothing when compared to the overall electrical power consumption of the vehicle.

    If there is concern about the amount of power that this consumes, then the answer would be to keep headlights off, except at night when they are needed. The exterior lighting probably consumes ~150W of power or so.

    To provide a little perspective, consider when 2G Prius is in regen mode and producing those little cars that appear on the MFD. By leaving your exterior lights on for a one-hour period, you are using up the amount of power that three of those cars represent.
     
  11. Rest

    Rest Active Member

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    True but, this is in addition to the overall electrical power consumption.
     
  12. qbee42

    qbee42 My other car is a boat

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    The glove box LED essentially adds zero to the overall power consumption. The tiny, tiny increase in power consumption doesn't warrant the extra cost and complexity of a switch. Adding the weight of a switch and extra wires would probably hurt the mileage more than the tiny draw of the LED.

    Tom
     
  13. pEEf

    pEEf Engineer - EV nut

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    The LED draw is under 20ma which is nothing in the scheme of things. If you are worried, simply unplug it. I suspect a little dirt on your car will use more energy than leaving the LED on!
     
  14. uart

    uart Senior Member

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    Ok lets do the maths.

    Say the car uses about 10 kW at low to medium speed (a lot more at high speed).

    Say the weight of the switch and extra wire is one ounce, then that comes to just a tiny fraction of the cars overall mass, about 1/50,000th.

    The energy consumption increases as the weight of the car increases, roughly in proportion to the weight at low speed though not so much at high speed.

    So a 1/50000th increase in weight would cause an increase in power consumption of about 1/50000th of 10kW = 0.2W at low speed. It's a lower proportion at higher speed but it's a proportion of a lot more power so overall the 0.2W figure is a good estimate.

    A LED of the type used in the glovebox typically consumes about 0.05 to 0.1 Watt depending upon the driver (circuit). So yes it seems like the always on LED might actually use less energy than even the minuscule amount of extra propulsion energy that a one ounce increase in weight would cause.

    You really need to give this a rest rest. :D
     
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  15. Rest

    Rest Active Member

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    It's doubtful that the extra weight is recordable in mileage reduction. The floor mats are much heavier. Besides a micro switch is a very tiny device, that you could blow off your hand.

    I may just add this feature in myself.
     
  16. qbee42

    qbee42 My other car is a boat

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    This is my point exactly. The weight of the switch is negligible; so is the power consumption of the LED. Read the post above yours: it does a good job quantifying the effect of both.

    Seriously, the decision to *not* use a switch was a very good decision. It doesn't add value, adds costs, and reduces reliability. Toyota made a good call on this point.

    Tom
     
  17. Rest

    Rest Active Member

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    But didn't you say this? "Adding the weight of a switch and extra wires would probably hurt the mileage more than the tiny draw of the LED."

    I'm saying the weight of a switch and (if) any extra wires, does nothing to the mileage, that is recordable anyway.

    Sure the power consumption may be very low, but I still think wasting any amount of power in a Prius just doesn't seem right. Besides LED light do burn out, I have experienced this on computers many times. So the replacement adds another expense down the road.
     
  18. uart

    uart Senior Member

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    Ok well I give up trying to explain it to you. So please go ahead and install this switch, and please do record the improved MPG's and report it here. You know that there will be none and you know that the switch would typically fail long before the LED does. So seriously what do you think you are going to achieve with this.
     
  19. Rest

    Rest Active Member

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    I never said installing a switch would give gains in mileage. So I'm not sure where you got that.

    Micro switches last a very long time, I personally have never had one fail. And when they do it's easy and inexpensive to replace them.

    If you had read my post, then you would have known what I planned to achieve.
     
  20. uart

    uart Senior Member

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    Honestly I have read all of your posts on the matter but I still cant figure out what you hope to gain by the modification. You want gain anything in mileage and you certainly wont gain anything in reliability.

    Actually this thread is really timely for myself also Rest. Literally just a few days prior to the start of this thread I noticed for the very first time that my glovebox light stays on. Initially I thought there was a faulty micro-switch and I was looking everywhere for the switch and obviously didn't find one.

    Now initially I had exactly the same reaction as yourself! I thought wow what a bloody silly design to waste power by having that stay on all the time. After looking it over a bit more however I noticed it was an orange LED and I also noticed that it was only on while the headlights were on. At that point I realized that the power waste was so close to zero that even adding half an ounce of extra weight would waste a similar amount of power. At that point I got over it.