Check gauges light and power power surges
 

For the life of me I can't figure out what is wrong with my truck.
A little background: the truck voltage meter reads about 9 and says check gauges.
It's done this for awhile now. At first i figured it was because of the weather outside (I live in Colorado). But now its 70 degrees out and it still does this. I replaced both batteries within the last couple months and also just recently replaced the alternator. Once the truck is started about 30 seconds later the gauge goes back to normal and the light turns off; however if i have either the headlights or interior lights on, they will get dim every 15 seconds or so then get bright again. This happens over and over.
Anyone know what could be the problem?
Thanks!:argh:

With the lights getting dim every 15 seconds and the voltage being around 9 it makes me think of the grid heater cycling on and off. Maybe check to see if that is functioning properly because the grid heater does pull quite a bit of power

Thanks for the quick reply! How would i test that?

Search on YouTube for grid heater diagnostics. I am on tapatalk other wise I would post video. Mopar1973man should be the youtubers user name.

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