overcharging problem

[green goat]

Approx. two months ago my headlights started flickering intermittently then they looked like they were on high beam all the time. Next came the intermittent glow of either and both alt. lights then on steady and the voltmeter is showing overcharging. I've been searching the forum and manuals then testing and replacing parts but still not any better.
replaced battery and alt2
still overcharging
replaced alt1
now voltmeter shows to be charging in the yellow
swapped alt1 out with one from friends truck and its overcharging(worked fine in his truck)
noticed while turning the ignition off that the voltmeter stays in the yellow sometimes, stays in yellow for a moment then drops to bottom of scale, or drops to the bottom of scale with turning the key off.

 

[Keith_J]

Check the fusible links from the 2-wire connector's red wire on both. Unplug the two-wire connector and measure the voltage with engine off with respect to ground. Should be front battery voltage for the left alternator, both battery voltage for the right alternator.

If zero volts, the fusible link could be bad. This is the sense line and it tells the alternator what voltage to output. If broke, the alternator will peg to maximum which will overcharge.