My red triangle warning light had been coming on and off periodically for about six weeks. The car continued to behave normally so I just ignored the red triangle until it went off, only to come back on in a couple of days. I finally decided to take the car to the Toyota dealer. They found (at least that's what they say) that the auxiliary battery was low and recharged it. The red triangle is now off. There's no reason why the auxiliary battery should be low because I use the car regularly. Besides, the triangle would frequently go off overnight, when the battery should have become even weaker. Perhaps the battery itself is at fault, in which case the triangle should come back on in the near future. In light of the above, and a couple of posts about the hybrid system failing suddenly, we're putting on hold our decision to buy another Prius.
The red triangle is back on! I noticed that the light switch had been left on all night, but the lights were off. Can this actually drain the battery (switch on but lights off)?
was the headlight switch in the Auto position as it has a small draw that activates the relay to turn the lights off. But shouldn't drain the battery over night. To kill the aux bat over night the draw would have to be approx 4-5 amps. well maybe a bit less with the little aux bat they use in the Prius. It doesn't have a lot of excess capacity as it's sized to just boot the computer.
Do you press the P button before switching off and lock the doors with the remote key? When I do that, all lights including the courtesy light, are shut off so I assume there is no drain on the auxiliary battery except for the clock.
