Alright everyone, I need your help. My 2003 Z06 has had some funky voltage readings. Cold starting and driving the voltage is ~13's and as the car warms up, it decreases slowly down to the mid 11's (plus a whine that I recently started hearing that increased with engine speed).
I received code P-1637 and, per the service manual, have come to the conclusion that I need a new alternator.
Before you ask, I have done the following (volt meter):
-Tested the battery volts with the car off, and with the car running with very little change.
-Tested the resistance between the battery and the alternator and got very close to 0 volts indicating a solid connection (no connection issues at the starter) when the car is running, pass.
-Tested the B pin and saw 5 volts, pass.
-Tested the D pin and got the same volt reading as the battery, pass.
Based off of all of that, The book tells me I need a new alternator. My alternator has no markings or stickers indicating the alternator that I need. 145amp? 110amp? GM (10316182) per GMpartsdirect is a 110amp. Is that the one?

 

I have an o4, both the 110 and 145 amp will work, I don't remember what year the switch was made to the 145 amp. Be careful with the replacement the excitation voltage for the Corvette is different from most replacements so having you old alternator is a benefit since you don't have to worry about compatibility.

 

You wont make a mistake if you go with the 110.