Lights flicker when starting up?

[ybkm]

2nd post of the day, I love this forum!! I have noticed lately that my 2003 Toyota Sienna CE has a flicker to the lights when starting up, especially when it is colder outside. I did a Google search about this, and found some people talking about this being a Toyota problem. No one seemed to know what caused it. It is annoying more than anything. Seems to clear up after several minutes of the engine running. But when the engine is cold, ALL lights flicker - exterior lights, dash lights, interior lights. These lights do not flicker when the car is off, so it seems to be an issue with the charging system. Does any one know what could cause this?

[kmahren]

I'm not sure this is a problem... when starting the car, most of the "juice" goes to the starter motor.... does your lights flicker any other time?

You might need a new battery.

[ybkm]

This "flickering" happens after the van is running. The lights dim with the starter motor of course due to the large amount of energy it takes to fire the 3.0 motor. That happens with any car. This happens typically more when the outdoor temp is cold, at least it flickers MORE then, but can happen at any temp. It seems to be related to the charging circuit, since the lights do not do this when the engine is off. After a while, it stops.....

[kmahren]

First, I would have the battery checked. then you might look for a bad or broken connection in the wiring. It may very well be the charging system, but I would eliminate less expensive options first... good luck.

[2006SiennaLE]

First, I would have the battery checked. then you might look for a bad or broken connection in the wiring. It may very well be the charging system, but I would eliminate less expensive options first... good luck.

+1

Since it happens while the van is running, a poor connection to/from the alternator is a likely cause. If the connections seem ok, it's probably time for a new alternator.

[pjksr02]

Sometimes when you go to the doctor with a cold, you don't need to get your tonsils out. My van has done this in extreme cold (say low teens and below) for many years. I've chalked it up to voltage regulation from the generator (alternator), and lived with it for the minute or three it's present. Then again, it never hurts to ensure a clean ground and sound electrical connections.

[Shodoug]

Replying late for others who might be search later...

Our lights were flickering pretty bad, and got much better when I changed the brushes in the alternator, at about 210,000 miles. The part was about $10 at a local alternator repair shop. The lights have gotten better still after having a bosch alternator put in at about 250,000 miles.

Doug

[tymorrisonheath]

Mine did this and then I replaced the battery. Fixed it right up.