Backstory I was driving home from a week in Colorado, I had smelled the battery off and on during the week. I was running lead acid. When I was coming through northern Utah the battery smell proceeded to get worse I checked the charging system at one gas stop and got 14.9 volts. I installed a AGM battery in St George so I didn’t have an issue driving through the California Desert. I contacted Wranglerfix he thought the voltage was a little high also. I installed my old PCM that has the transmission communication issue and have he same charging voltage. (Never had any charging issues with this PCM) I am looking for someone that can back probe the alternator field circuit while running to give me field voltage vs charging voltage and base battery voltage. I have added a few picture of what I’m looking for. Does anyone have any information on the battery temp sensor, it is not in the wiring diagram. I assume just a thermistor going to the PCM?
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