Battery gauge reading low voltage

[arizonabronco]

Thanks in advance for any information. I have a 1989 5.8L and 2 nights ago, the battery light came on suddenly and the voltage on the dash gauge dropped to just outside the low/red area. Over the last two nights, I've replaced the battery (Checked it first. It gave a bad initial reading at the parts store and it was in warranty so they swapped it out for a new one), the alternator, the positive and negative battery cables and the serpentine belt. The only thing I haven't replaced is the cable running from the solenoid down to the starter. The battery light is no longer on (it went out when we replaced the alternator), but I still have low voltage/reading on the battery dash gauge. It starts strong, stays running and appears/feels to be driving normal. I am taking my truck tonight to get the battery and alternator outputs checked at the parts store in case they are faulty (again, they are brand new). What else could be causing this reading on the gauge? Thanks again for any ideas!

 

[BroncoJoe19]

If your alternator is putting out 14.4 volts and lets assume that it is.

The low reading on the guage may just be a bad guage. Otherwise my first guess would be a bad ground to the instrument panel/cluster. I'd look for a ground on the bottom of the dash panel about where your knee would hit the dash if in a front end accident. Make sure it is clean and tight.

Ofcourse I am just guessing because you haven't had the alternator tested yet.

Once you get back to us, we can go into greater detail, and actually look at schematics.