I have a 2001 Vitara JX. I have an intermittent pulsing of my lights, headlights, dash lights, tail lights ect. It comes and goes, have not been able to pinpoint what causes this. I'm on about a 2 month not pulsing streak. Now any time they may start pulsing again, they could pulse for a week or more before stopping again. This problem has gone on since the vehicle was bought brand new. It's been to the Suzuki shop to be looked at and of course while there, they didn't pulse. Anyone with a suggestion on what the problem my be. Any help would be appreciated.

You'll need to provide more details - what is the "pulse rate" like, slow, once per second, fast, four~five times per second?  Does it happen only when the engine is running?  Next time it's pulsing get an analog volt meter and connect it directly across the battery terminals, tell us what the needle does.

My guess is the alternator is the source of the issue, but that is only a guess.

Replaced alternator still have problem. The pulsing goes with engine speed, at idle it's  slower than when driving down the street or highwsy.