Ford Repair: Battery, 89 ford ranger, intermittent light

Question
Have not had any problems recently with my 89 ford ranger. This AM when I started the truck the battery light was on and the lights were dim, but every thing seemed to be working ok. As I drove into work about 16 miles, the battery light was intermittent at different speeds. Belt feels tight, Is this a belt or alternator problem? Funny sometimes the light would go out when I used the turn signal. Did not see any difference on the voltage meter during driving and intermittent light.

Answer
probably not belt but i can't answer the question and nobody else can either without it being tested-alternator/battery or loose/corroded connection can be the problem-if it is a battery it will eventually ruin the alternator by causing it to overcharge if it is alternator it can ruin battery by not charging enough-have it checked.