Replacement alternator from autozone puts out 16.5 volts. However, if I pull out the PCM/ alternator fuse, it puts out 14.3 volts, but the battery light comes on.

Will it destroy anything to run it without the PCM alternator fuse in the circuit to get the right voltage and let the battery light stay on or do I need to replace the PCM. (The battery charges up OK )

 

My 2008 Mazda CX-7 is having a similar problem. Out of no where, all of the dash lights came on. CEL, airbag, traction control, abs, battery, etc. On top of that, the radio would only work when you turn the key on, but when the car is running, it won't work. The speedometer also does not work and when driving it doesn't shift back down to first gear. I took it to a Mazda dealership and they said it was the alternator; it was putting out 19 volts (normal ~13.5). They quoted me $700 to replace it and they said it would be a week before they could get the part. So, I found one at an auto parts store and replaced it myself. It is STILL putting out 19 volts! I ran the old alternator and the battery up to the auto parts store and had them test them and they both were good. The dealership is baffled. At the moment, I am waiting to hear back from them because they had to call their tech line to see what it could be. I've swapped the relays and such to see if its a bad relay. Any help would be greatly appreciated!

 

Alternators need a voltage regulator. In my Windstar the voltage regulator is built into the alternator. But I have learned that in some vehicles voltage is regulated by the PCM. It might well be that this requires a new PCM.

Please verify, I don't know your tribute's system. I am just pointing out a possibility.