Battery not charging message but it is sometimes

[EfiniMotorsport]

After finally getting my 04 Denali back up and running it was fine for a few weeks and now I'm getting a battery not charging message. I put a new interstate battery in when I did the transmission a month ago. I went to take it out 2 weeks ago and when I started got the battery not charging message. Checked the battery with the truck running and it was under 11.5v. I got a used DC power engineering 270a alternator from work and had it tested at autozone and it passed. When I installed the alternator I was still getting the message even when the voltage gauge was showing 14v and meter was showing 14.5v. I tried restarting the truck a few times and sometimes the alternator wasn't charging at first but would start charging if I disconnected the 4 pin plug then plugged it back in. I don't want to just throw a new alternator at it until I confirm that's the issue. I know these trucks can have issues with the cluster as well. Anyone have any suggestions on testing?

 

[Doubeleive]

After finally getting my 04 Denali back up and running it was fine for a few weeks and now I'm getting a battery not charging message. I put a new interstate battery in when I did the transmission a month ago. I went to take it out 2 weeks ago and when I started got the battery not charging message. Checked the battery with the truck running and it was under 11.5v. I got a used DC power engineering 270a alternator from work and had it tested at autozone and it passed. When I installed the alternator I was still getting the message even when the voltage gauge was showing 14v and meter was showing 14.5v. I tried restarting the truck a few times and sometimes the alternator wasn't charging at first but would start charging if I disconnected the 4 pin plug then plugged it back in. I don't want to just throw a new alternator at it until I confirm that's the issue. I know these trucks can have issues with the cluster as well. Anyone have any suggestions on testing?

first thing to do is clean the battery cable connections and grounds, even if they "look ok" use a wire brush, unbolt them and scrub both sides at battery, alternator, block, frame or anywhere else you can reach or access.
then see what happens.

 

[EfiniMotorsport]

I wired wheeled everything. I also made a new cable from the alternator to the power distribution point.

 

[Doubeleive]

@rockola1971 any idea's with the 4 pin?

if worse comes to worse you can just run a 12v exciter to it and make it work

 

[EfiniMotorsport]

I checked voltage on the brown wire in the 4 pin plug (there's 3 wires in it, center of the 3 is brown) and it's 10.5v which from what I can find it's supposed to be. It goes through a bulb to drop voltage

 

[Doubeleive]

I don't know a whole lot about the 4 pin systems other than you can make it work with a voltage feed if you have to, but otherwise it should have at least 13.4v pretty much anytime the engine is running, it's not like the newer 2 pin rvc regulated systems.
have you looked at the pcm harness and fuses?
there is also a off chance that it could just be a funky alternator I have had problems with those aftermarket (off-brand) alternators with intermittent operation. so I bought a mechman and no further issue's

 

[EfiniMotorsport]

The DC power isn't an off brand. I called them and they said there's usually a harness that runs a wire from the + terminal to the left pin on the 4 pin plug. I'll give that a shot and see. They did say if the regulator went they can fix it for about $50. Much cheaper than even a stock replacement.

 

[Doubeleive]

The DC power isn't an off brand. I called them and they said there's usually a harness that runs a wire from the + terminal to the left pin on the 4 pin plug. I'll give that a shot and see. They did say if the regulator went they can fix it for about $50. Much cheaper than even a stock replacement.

wasn't familiar with the name, looks like they use the same press fit diodes as mechman and the newer style oem.

 

[EfiniMotorsport]

For the price they better do it right. They also use a billet front cover which looks good

 

[Doubeleive]

For the price they better do it right. They also use a billet front cover which looks good

Ya that's about what I paid for my mechman, they are pricey