2009 S60 2.5T, when car is at idle the interior dome light flickers. I checked to volts on the battery and it was okay, car is over 3 years old so installed new battery and this did not help.

Any ideas, or is this normal???

 

maybe a diode out in the alternator i would have it check before replacing or see if the ground or power varies to the ground or power of the lights at idle for some reason. there is a tsb if you have aftermarket electrical stuff it has to be grounded after the battery monitor sensor. it says it can reduce alternator out put.