Mechanics

WHY IS MY CHARGING SYSTEM LIGHT STILL COMING ON AFTER REPLACING THE ALTERNATOR?

2003 Mazda 6 • 154,000 miles

My 03 Mazda 6 charging system light came on the other day. Took it to see what was wrong. Alternator. Replaced it. The charging light still comes on. Had it tested again. The alternator is sending too many amps to the battery. I have thought it could be the voltage regulator seeing as how this car has an external as well as an internal(alternator) regulator. However I have been told that it is the computer and I need to have that looked at. All I need is some advise on the next step. Thank You.
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Gman316
July 2, 2012.



No external regulator the PCM controls ALT output so if high then PCM is a fault

Docfixit
Jul 2, 2012.
Thank you for clarifying Docfixit. That actually makes more sense.

Tiny
Gman316
Jul 2, 2012.
Most manufactures doing that now say it provides better current flow to system but does add cost to ALT repair.

Docfixit
Jul 3, 2012.
Good Afternoon,
I am having the same problem with my 04 Mazda 6, 2.3L 4cyl. I had it checked at Advance Auto the other day. Battery good, starter good, but alternator putting out 0 current. He told me to check all wires first before changing anything. It started after driving from NC to Maryland Sunday night. I got home and the battery light flickered. Drove it to work on Monday but when I went to go home, battery light came on and stayed. Went to pull off and car went from 1st to 3rd and would not downshift to 1st when I stopped. I had to take off in 3rd gear. I switched the car off and was now in 1st. Also, it would not manually downshift to 1st either. CEL (Check Engine Light) also on - Coolant Temprature Low (that will be another post because I changed the Coolant Temparature Switch and CEL stayed off for about one month).

I read on some other sites that 1 guy changed alt 3 times and CEL was still on so I don't want to hane to go through that process. Is there a sure fire way to determine the problematic source? BTW, not good with volt meter!

Thanks

Tiny
CATWillMazda-6
Jul 4, 2012.