I have the following symptoms: Idle voltage 11.5-12.5 fluctuating. Running voltage @2500 RPM and up: 12.5-13.5 fluctuating. I am assuming my alternator is going out. Fortunately, I have two spares...so I'll probably just swap it out, but is there anything else to check first? Any voltage regulators external to the alternator, or anything in the under-hood fuse box or SJB to check? Any fuses that blow which can cause those symptoms? I am not throwing any codes.