hi , i recently bought a 1997 civic , love the car it drives great , but when driving at night i notice the dash lights and headlights tend to dim then return to normal up and down about every 20 minutes when i am driving , any iideas on problem ? battery connections are tight, could it be the altenator ? or some electrical short? thanks for the advice

Could be the alternator. Take it to Autozone (or pretty much any other car part store) and they'll do a free test on it.