M1028 Charging Anomaly

[Unclewally]

Both Gen1 & Gen 2 lights come on when the key is turned on. Once started and idling, Gen1 light is on (dim). Once driving, the Gen1 light goes out completely. While at speed - the volt gauge is on the high end of the green into the orange. The volt gauge has always been on the fat part of the line right beneath G in Gen previously. After awhile the Volt Gauge pulses slowly at speed. If you stop at a light/stop sign, the volt gauge goes to where it used to sit (middle of the fat part of the line) and the Gen1 light is on dimly.

Batt Voltages 13.8 Front/13.3 Rear

Red Wires at Alt's (key off) - Battery Voltage
Brown Wires at Alt's (key off) - nothing
Brown Wires at Alt's (key on) - Battery Voltage
Grounds are present on both Alt's

I cleaned all the connections on the Alt's

I have deduced that the issue is in one of the Alt's (and not the truck wiring). I suspect the drivers side since the Gen1 light comes on at idle. I ordered diode trio's and voltage regulators and plan on rebuilding the Drivers side first. Form the looks of the volt gauge I would think it's a voltage regulator....

I am also going to have both batt's tested tonight on my way home as the rear batt is a little weak on voltage.

Am I missing anything?

Brian

In rereading this, I will be checking continuity from ground pin on alt's to the neg terminal on the front batt.

 

[Drock]

I had a similar problem a few months ago with GEN2. I did the basic rebuild on the ALT, but still no change. As it turned out the turbo baked the passenger Alt & 1 of the batteries. I'd recommend having both ALT's tested before & after your rebuild. You'll just need to show the person doing the test the isolated ground post. As our ALT's don't ground on the case.