Battery warning light on when cold V70 2.5

johnsgotwood · Post by **johnsgotwood** » 02 Feb 2009, 16:21

When I start the car from cold everythings fine for about 15 seconds then out of the blue the warning light comes on. Not glowing but dimly as if some power is being distributed but not all. This carries on until the car has reached its normal temperature then disappears not to be seen again until the cars cooled down a bit and restarted.

It seems more likely that the belt or tensioner is the cause of the problem but I was wondering whether anyone had heard of an alternator needing to warm up before working. I am a little concerned because the car is an automatic so I can't bump it in the event of a flat battery.

Can it be tested on the car or does it have to be removed?

Post by **MadeInJapan** » 02 Feb 2009, 16:46

You can take it to an AutoZone and they will load test the battery and alternator for free...they have a cart that they'll roll out to your car to do this. I suspect a weak battery or corroded battery/ground cables...cold, there's a problem- warm, there isn't.