Alternator od battery?
 

Lights flare up when engine is revved up. Battery or alternator?

Re: Alternator od battery?
 

alternator would be ur best bet. but if you have a multimeter u could just check it at the battery to see what it is putting out for volts. should be over 13.6 when running at idle. if not then bad alternator. also are you havin any other problems with power like trying to start or no start conditions?

Re: Alternator od battery?
 

No other issues . I just noticed the lights flaring up a few days ago. Starts fine etc. I checked battery at idle its running around 14.