I'm having an issue with our 2001. When I turn the ignition switch forward to the accessory mode--with headlights, fan, wipers or any combination turned on- the displays will fade indicating a drain on the system. There is a drain, in fact, because when I try to start the car after a second or two in that mode (and, quite often, if I just turn the ignition directly to start with said accessories on) the car will not start. If I then turn all the electrical accessories off, the Prius so far has started every time, albeit with a slightly longer than normal delay.<br><br>Has anyone had this experience? And was your dealer able to fix the condition?<br><br>John in Seattle

I've never tried to start with the headlights on, but I have actually been impressed with the Prius that NOTHING seems to dim the lights, even before starting (which is when the high-voltage battery kicks in to help the 12V battery out).<br><br>Sounds to me like your 12V battery is questionable, which implies to me that something might be wrong in the inverter/charging circuit.<br><br>I'd show the dealer.<br><br>Burns

Actually, let me put a caveat: Do you drive for very short trips and not too frequently? If so, the 12V battery might not have time to be charged up. It is fairly small as car batteries go, so it will drop more quickly than you might expect. Of course, it does not have to power a starter motor, which means that in order to start, all you need is enough juice to boot the computers.<br><br>Burns

johnncat 11/30/01 4:18 pm:<br><br>&gt;&gt; I'm having an issue with our 2001. When I turn the ignition switch forward to the accessory mode--with headlights, fan, wipers or any combination turned on- the displays will fade indicating a drain on the system. There is a drain, in fact, because when I try to start the car after a second or two in that mode (and, quite often, if I just turn the ignition directly to start with said accessories on) the car will not start. If I then turn all the electrical accessories off, the Prius so far has started every time, albeit with a slightly longer than normal delay. &lt;&lt;<br><br>Sounds like either a bad connection somewhere to your 12v accessory battery, or a bad 12v battery... (A (VERY!) few people have mentioned that their car doesn't like to start on occasion, turns out it was a dud 12v battery, or they left some light/accessory on overnight and needed a jump...)<br><br>(The little 12v accessory battery runs the accessories. When you start your car, the 12v battery powers the computers (ECUs), which then use the ~270v HV battery pack to start your engine/motors. (so, if you have a dead 12v battery one morning because you left a door ajar and the interior "dome" light drained the 12v, you can't start your Prius without the usual "jump" from another donor car.)) When the car is on, the 12v is charged off of the ~270v HV battery, which is charged through regen braking or from using the engine/motors as a generator.)

Our driving is pretty varied, ranging from short to extended, and rarely going more than 24 hours between trips. I suspect we drive enough to retain sufficient charge, so the theories regarding the charging circuit and/or the battery itself are plausible. It's off to the dealer with it this week.<br><br>Thanks,<br><br>jh