New to site. M1009 Charging Issues

[CornfedM1009]

Hello from Southern California. New to site. Been reading all theads on charging system still can’t figure out what’s going on with gen 2 charging side.
I have owned my M1009 for 8 years had both alts rebuilt about 4 years ago. Everything was working fine until last Friday. GEN 2 light would not come on and back batt completely dead. Checked voltage on GEN 1 and it’s putting out over 14 volts. GEN 2 only showed 1.6 volts. After reading up on charging system switched gen 1 to gen 2 spot. In stalled a 1984 Cadillac Eldorado 5.7 diesel 100 non isolated ground altin place of gen 1. Still same problem.
Now this is where some of my dumb questions com in even with dead back battery would gen 2 still put out 24v or does battery need to be replaced. After reading and following voltage testing at two prong plug on gen 2 key off I had 1.6 v on power wire and 0v on excite wire key on 1.6 on power wire and 1.6 on excite wire with ground on rear battery. If I found on front battery voltage is 14.01 volts on readings. On gen 1 all readings are good.Would like it figure this out before I sell. I have been repairing and replacing a lot of things on M1009 for the reason of buyer being a Vet. This is the only reason taking time to fix everything. If it wasn’t for him being a Vet I would sell it as is and let buyer know what problems it has . Thank you for any I’m put. Also I hope I’m posting in right area. If not let me know. Thank you.

 

[MarcusOReallyus]

You should always start all troubleshooting with fully charged and tested batteries. Otherwise you could be chasing your tail for quite a long time.

Start there.

 

[CornfedM1009]

Ended up replacing rear battery because would not take a charge. Replaced alt 2 with alt 1 then installed a 1984 Cadillac Eldorado 100 amp alt for alt 1. Charging system working now. Charging at 28 to 29 Volts. Is gen 2 light supposed to flicker when turning on turn signal? Thank you for your response. Just making sure everything is working properly before New owner picks it up.

 

[MarcusOReallyus]

Is gen 2 light supposed to flicker when turning on turn signal?

Nope. Check your grounds. Start with the one up under the dash. It's a 6-pronged thingamabob screwed into the parking brake mount, or near it (exact location varies). It's normally got ONE black wire going to it. That's the ground for everything on the dashboard.

Also check the grounds for the lights themselves.

And remember, when electrical things get weird, clean your grounds.