BATTERY NOT CHARGING Update***

Chevrolet1698 · March 30, 2018

My apologies for not being active on here in quite a while. Last time I was, I asked why my ‘04 Silverado 1500 read the message “BATTERY NOT CHARGING” in the Driver Info Center when the alternator and battery were charging after 5 or so tests. Despite that, the truck would also lose voltage and stall out mainly while driving slow in parking lots, requiring a refire. So I had the Auto students at my local tech school diagnose and fix the problem.

They found 4 spliced open wires from the alternator to the PCM, the latter of which needed replacing along with a bad ground in the alternator harness, which too had to be replaced.

Is this unusual to anyone? Or is this a common problem?

bent67iron · April 9, 2018

OK, I have some questions; I am looking at GM eSI (Electronic Service Information), 2004 Silverado 2WD, Gas. It show only 3 wires from the regulator. 2 wires go to the PCM, Battery and one going to the Brake Warning System in Hydraulic Brakes, that I could look into. But, the PCM sends a class2 serial data message to the IPC if you have a charging system problem, thus your message.

As for "4 spliced" wire open....Did someone change the alternator from the original to something newer? There is no reasons for splices from the factory, at least here. Best practices is to solder the wires and cover with shrink tubing. The ground is provided thru the case thru the mounting, but it does not stop somebody from putting on an external ground. (I would need your 8th digit of the VIN to I.D. the engine)

Your truck is on the edge of having a AD244 Delphi alternator or a Denso NG44 (Or something like that). They do not share voltage regulators. Four wires can be found on the 5.3L Tahoe in 2003, with one with producing 07. volts for a vacuum pump at the booster, called "Brake Assist". This pump has an internal switch to sense low vacuum, 8 inches or less I think. (Like towing uphill) This also generates a message on the dash if vacuum assist kicks in on the AD244 alternator to PCM, via class2 to IPC. I would just make note of what alternator you have. If it's working now, good! You can I.D. your at alternatorman.com and find updated diode stacks to increase amperage output and other parts for service.

Chevrolet1698 · April 23, 2018

On 4/9/2018 at 1:18 PM, bent67iron said:

OK, I have some questions; I am looking at GM eSI (Electronic Service Information), 2004 Silverado 2WD, Gas. It show only 3 wires from the regulator. 2 wires go to the PCM, Battery and one going to the Brake Warning System in Hydraulic Brakes, that I could look into. But, the PCM sends a class2 serial data message to the IPC if you have a charging system problem, thus your message.

As for "4 spliced" wire open....Did someone change the alternator from the original to something newer? There is no reasons for splices from the factory, at least here. Best practices is to solder the wires and cover with shrink tubing. The ground is provided thru the case thru the mounting, but it does not stop somebody from putting on an external ground. (I would need your 8th digit of the VIN to I.D. the engine)

Your truck is on the edge of having a AD244 Delphi alternator or a Denso NG44 (Or something like that). They do not share voltage regulators. Four wires can be found on the 5.3L Tahoe in 2003, with one with producing 07. volts for a vacuum pump at the booster, called "Brake Assist". This pump has an internal switch to sense low vacuum, 8 inches or less I think. (Like towing uphill) This also generates a message on the dash if vacuum assist kicks in on the AD244 alternator to PCM, via class2 to IPC. I would just make note of what alternator you have. If it's working now, good! You can I.D. your at alternatorman.com and find updated diode stacks to increase amperage output and other parts for service.

To be honest, I’m not a pro at electrical systems, but the engine is an LR4 4.8L V8, VIN code “V”. And the alternator I have is the original Delphi Automotive. 105 amp, I believe.