Hey guys, My '96 Chevy Z71 w/5.7l is having alternator problems. The head lights & cluster lights "pulsate" when turned on. I was told that the rectifier is probably bad. I was told that I could check for AC volts across the battery terminal with voltmeter when the engine was running & if it showed any ACV, then one or more of the diodes are bad allowing AC current to "leak" or flow. Is this correct? This being said, I currently have the 105 amp alternator w/internal fan on the truck. Can I "update" the replacement with a 140 AMP that has the external fan? will this bolt, plug & play without any mods?