96 Tahoe voltage drop

[962door]

I have a 96 2 door Tahoe and when I have the headlights on with the heat on full blast and it is in gear it has a bad voltage drop. It has some when it's not in gear but a lot worse when it's in gear. I've replaced the battery, alt, belt tensioner. Any help would be great. Thanks

 

[about20ninj45]

I have a 96 2 door Tahoe and when I have the headlights on with the heat on full blast and it is in gear it has a bad voltage drop. It has some when it's not in gear but a lot worse when it's in gear. I've replaced the battery, alt, belt tensioner. Any help would be great. Thanks

Sound like you need to clear up your grounds and check your output from your battery/altenator

 

[SunlitComet]

agreed. but also power supply wires.