Correct alternator voltage
my trucks been reading 13.6 on my svt programmer for 2 yrs. Last week had to boost the truck twice. Took both my alternators off and took them to auto value and the auxiliary alternator failed. So I replaced them both. I also replaced my battery’s with 2 new 850 cca batterys.
same ones that I took out of truck. Now my gauge is reading 13.2 -13.6. And it fluctuates while I’m driving. What do you guys all think. I isolated both battery’s and there reading 13.4. The alternators are both charging at 13.8-14.0. But my dash gauge svt display is jumping around everywhere. I cleaned all the wires before putting the battery’s back on and all the alternator connections.
Fluctuating voltage can depend on the channel monitoring, as the PCM reads in 0.5v divisions rather than 0.1v with one channel. However, the two-wire connection at the alternators can also lead to a variation or fluctuation. One of those wires is a sense wire, sensing the battery voltage for the alternator to respond.






