Isuzu blower surging

The blower on my Rodeo started surging (usually at slow speeds). This went on for a few weeks. Then the radio started shutting off when I would use the turn signal. Finally, the vehicle quit running one day. I put a new alternator in it and it seemed to run fine for a week. Now the blower is starting to surge again and I am worried the same sequence of events will happen. How can I diagnose what is happening?

-ak_hunter

Where did you buy the alt from? Isuzu's are very particular about their alts (search and you will find more info on it here).