Okay, the first thing is to see if it is something in the dash or if it's the PCM itself. The charging regulator is part of the PCM, and it sends data to the dash to control the light. The description sounds like the control circuit is cutting out. First you need a meter and try testing the output. You put the meter on the battery and measure the voltage, now start the engine and measure again. You should see at least 12.6 volts from a fully charged battery, and when the engine is running you should see around 14 volts. I suspect that you will find that the system starts charging and then drops out. So first we want to check the fuses, just to be sure, so check fuse number 10. If it is good, then the next testing requires a scan tool to see if the PCM is trying to control the alternator.
https://www.2carpros.com/articles/how-to-check-a-car-alternator
Mar 18, 2025 at 7:47 PM
