1998 Grand Prix GT alternator won‘t charge

I never really checked the charging system (i.e voltage) but I assume it was ok. Car seemed to be running fine though I haven‘t driven it for long. I hit a big puddle hard that I couldn't see one day. Then drove through deep water. Changed the alternator, trac off light comes on, blower blows less, then abs light comes on, all after about 1 minute, and I even revved the car a bit. Iow battery isn‘t being charged by the alternator. Could someone please tell me what to check. Someone said it's the starter, but car starts fine. This happened about 2 weeks ago. Could something still be wet? Thanks in advance.

I would check the main fuses under the hood fuse box.... looking for the highest fuses such as the MAXI fuses. 60A or higher. Bit since your there, check them all anyway. I think the Alternator sense fuse is there too (smaller fuse maybe 10 or 15A). Use a voltmeter to check, don't go by eye.
That would be my #1 guess.

Someone thought the starter? Lol wow. Literally, the only thing the starter does. .. is start.
It's job is done after cranking.

I hope my 1st statement helps. Good luck & keep us posted with your findings.

Check voltage at alternator output and battery when car is running. Both should be about 14.5V. If the alternator is not generating that voltage, then check the controlv inputs to the alternator... In the connector leading to the alternator. I'm sitting in the airport so can't tell you what the expected inputs are but I'm sure that can be googled.

The charging system is fairly simple. Maybe you can find a schematic to guide your troubleshooting.

Good luck.

I assume this means you don't have a voltage gage in you I/P cluster?

If you do, what is the voltage reading as you drive the vehicle?

If you have a voltmeter, put it across the two battery terminals.....

A fully charged battery should read 12.6 volts.....

Start the vehicle.....should get a reading 13.5 volts or higher, with nothing on.....

Get the car to normal operating temp......turn lights on, turn blower on high, turn your rear defogger on....this loads the system......what is your reading.....want around 12.0 volts or higher....now rev the engine to 2000 rpms, and voltage should rise to at least 13.0 volts, if it does the alternator is ok...

If the alternator is not charging, first check the large red wire going into the back of the alternator for BAT voltage....if no voltage, check for a blown fuseable link....