Thanks guys for joining the Mechanix Advantage community! I’ve started in electrical training but there will be more to come, Air conditioning. Driveline, Hydraulics the works. Drop a question in a discussion board and I will work to make a piece of something to answer it.

Wassup everyone! Need some help with the Cummins. My truck is throwing a check gauge light. Light is coming on for low battery voltage. When I start the truck the check gauge is on and stays on at idle. On my tuner screen the system voltage is 11.8 volts and will drop as low 10.7 volts. If I turn on the high idle switch the check gauge light goes out right away. The battery voltage reading goes up to 12.8 volts. No matter how long the high idle switch is on for as soon as it is turned off the check gauge light comes back on and the battery voltage goes back down to 11.8 volts. When I drive the battery voltage goes up to 12.8 volts at any speed between 15 kph to 30 kph with light load. If full load or highway speed the battery voltage reads 13.2 volts. Check gauge light is not active. After a 20 minute drive to parked the battery voltage when parked is sitting around 12.9 volts With no check light on. Other times the battery voltage will be at 11.8 volts with the light on. I have tested the batteries, both my batteries passed showing good CCAS and OCV when disconnected fully from truck. Battery connections are clean and tight. When running at idle checking the alternator with multimeter is reading 12.9 volts. With high idle on is at 13.5 volts. All connections on alternator are clean and tight. Belt is in good condition and tensioner is adjusted properly. Batteries are a two years old and I replaced the alternator last year. Haven’t had any issues until the 2 months. Issue seems to be getting more constant. I have not hooked up an amp clamp or connected batteries to a carbon pile as I do not have one lol. Let me know what you think 👍🏻