1999 Chevy Suburban lights pulsating

I have a 1999 Chev Sub with a few electrical issues. The lighting system (all, including domes and displays(radio, etc)) pulsate somewhat rapidly. I've been told alternator, but I wanted to get your opinion before making the money plunge. The other "issue" was the beast wouldn't start (turn key=no response) until I would jiggle the positive lead on the battery. After several attempts of trying the key/jiggling the cable, it would finally start. I've cleaned the leads/battery terminal, so far seems to help. Pulsating is still there, though.I don't know if the 2 "issues" are related or not. What do you think?