Service charging system

[97audia4]

Alternator took a dump on my yesterday night but I was able to make it home.

Got the new one installed this morning before work but the batteries might be dead for good.

Last night batteries tested at 9.4 volts

After installing the battery light was still on but went off briefly on the highway and then back on while in stop and go traffic.

 

[97audia4]

Well two new batteries and it's still not charging correctly . New alternator is on and is putting out 14.5 to 15.5 volts, passenger side batter is already at 11.4 volts while running and drivers side battery is 12.5 while running. This is after 5 miles after new batteries and letting it idle for about 10 minutes

I need to check grounds now, passenger engine side ground is tight but I can't see where the small ground off of that goes too.

Any insight is appreciated.

09 Yukon Denali xl with the 6.2

 

[97audia4]

All grounds we're good and clean but I did find the mega fused trashed . Ordered one from the dealer and will be installing today.

 

[thompsoj22]

read my thread "chasing low voltage" change battery current sensor module, install 2" overdrive alt pulley and verify the charge circuit wiring integrity and your charge system will change completely. idling for ten minutes is placing the alt under unsat test as it is spinning below its rated rpm for max output. RVC will work alternators to a point of failure IMO. The overdrive pulley is an absolute necessity!!!

 

[Doubeleive]

I'm thinking it's a fuse or still possibly a ground wire, from what I know the NBS trucks ground wires can corrode from the inside, you do not need to change the pulley, if that was the case there would have been a recall years and years ago, also if your mega fuse was burnt or melted that's also a sign of a bad ground or your old alternator fried it which is possible but pretty unlikely.

 

[97audia4]

I'm thinking it's a fuse or still possibly a ground wire, from what I know the NBS trucks ground wires can corrode from the inside, you do not need to change the pulley, if that was the case there would have been a recall years and years ago, also if your mega fuse was burnt or melted that's also a sign of a bad ground or your old alternator fried it which is possible but pretty unlikely.

Water got behind the mega fuse and grounded against the fire wall where a spot was rubbed through.

 

[Doubeleive]

yep that would a problem right there

 

[thompsoj22]

That **** fuse is a good find and absolutely an issue! replacing it will get the circuit back to designed function. But i still advise researching "overdrive pulleys" on the alt. measure the alt/crank pulleys, devide the large by the small than multiply by the "idle" RPM and i think you will find the alt is spinning below it's rated output. Add the overwhelming draw of electric accessories and a little RVC and the design seems flawed. Or just keep running it as the factory produced it. Also "Doubeleive" google GM RVC complaints and review the info, i simply fixed it as opposed to trying to sue GM with a class action in regard to RVC as you will see many other owners tried. Im not saying you are wrong, just defining how i reached the decision to change the pulley and what a difference it made.

 

[swathdiver]

That **** fuse is a good find and absolutely an issue! replacing it will get the circuit back to designed function. But i still advise researching "overdrive pulleys" on the alt. measure the alt/crank pulleys, devide the large by the small than multiply by the "idle" RPM and i think you will find the alt is spinning below it's rated output. Add the overwhelming draw of electric accessories and a little RVC and the engeniering design is flawed. Or just keep running it as the factory produced it. Also "Doubeleive" google GM RVC complaints and review the info, i simply fixed it as opposed to trying to sue GM with a class action in regard to RVC as you will see many other owners tried. Im not saying you are wrong, just defining how i reached the decision to change the pulley and what a difference it made.

Why would anyone sue GM over RVC when all they have to do if they don't like it is to unplug it?

My little one drained the battery a couple of months ago. Got jumped and the next day hit the road and within 3 hours of highway driving it was fully charged again.

As for me and my house, now that I know what RVC and EPM are and do, I think it's pretty cool. In the old days we stuffed the biggest batteries that would fit under the hood and upgraded our 55 amp alternators to 60, 63 and then 80! By the mid '80s we were astounded when GM came out with 120 amp alternators thinking how could we ever need more? LOL

 

[97audia4]

My voltage never fluctuated at all while I have owned it. Now it's steady and above 14 at all times .