D3g. Parking brake/hystat lite on

Helping a friend out with his d3g, Was driving along an just stopped in its tracks, both lites came on an want go out, checked all fuses, borrowed another friends laptop an used ET, there were a list of hystat codes listed , but main code was the 41-4 code low 8voltdc supply, Cleared every code out except this active one, from what I’ve found useing the bootleg cat sis software/ET it refers to checking alternator, well it was bad an was reading differ readings here an there on my main post, An was extremely hot an actually turned the pulley black an crusty from heat, also water pump was shot, replaced them both an got the chargeing back stable, lites still on, codes for low 8v still active, When trying to trouble shoot codes threw ET it want open it up in sis due to adobe reader isn’t working properly. Looked around online an see where few people said check all grounds, load test battery’s (brand new from bad alternator kept draining them) looked over wireing harness for rat issues, With the amount of stuff I’ve removed from belly pan I think there was a Bigfoot living in there, even found lots of big bones . But never saw any chewed on wires, I removed left side floor step cover at fuse panel an check the wires in several plugs, had water in one connector, rinsed it out with parts cleaner, checked J1 an J2 connector, good an dry, no crusty pins anywhere. Few people also said the check foot throttle potentiometer for the 8v. An saw someone said the left drive motor speed sensor, I did see a sensor on the front side of the left drive motor, the sensor is oil an seemed to have a lil plastic cover over the end of it where wires come out of it. Actually thought that was the brake pressure switch that tells the brake lite to go off. Hadnt seen this problem in some yrs. I would guess that the 8vdc supply is supplied from the ecm when everything is operational but what are the things that prevent this from be correct voltage, Seen people say check the sensors. Foot throttle does seem like at times it on idles up at bout 85 percent sometimes. But I didn’t check the percentage outputs from it in ET data. But if it was having ft throttle sensor issue wouldn’t it had a code for it too. Or speed sensor codes, Well it does throw the brake pedal an ft accelerator codes for low voltage, but they do clear out with other codes except the 41-1 8vdc low supply? Thx for any advise an help guys.