Blower fan cutting out with certain power draw.

[iboughtatahoe23]

About 4 months ago I replaced the blower motor resistor due to the my HVAC not blowing at all, thought it was showing it was working no air was coming out. Replacing that part fixed it. No issues for a while, until now. Now my ac blows cold, but for some reason on hot days if there’s too much power draw the Fan will cut off for a split split sec and kick back on. It’s only if it’s on high. If I pull a window switch to roll up the window it will do it too. I haven’t tested it other than with the AC on. Also my headlight bulb went out. I tested the blower motor on the battery it runs fine. I tested the connections from the dash as well (about 4 months ago when I replaced the blower resistor) Idk if there is something weird going here as I did leave the sun roof open in the rain when I first got it almost 4 years ago now. It dried out fine. I guess it’s not urgent. I jsut can’t use the blower on high.

Edit: forgot to mention I am using an aftermarket refurbished alternator. I tested the battery under load and without load. And I I was getting high readings regardless. I think it was 14.8v? I used a Multimeter.

 

[iboughtatahoe23]

Okay, here's my situation summed up, sounding better I made a lot of typos ‍lol

About four months ago, my HVAC stopped blowing air, even though the controls looked like they were working. I replaced the blower motor resistor, and that fixed it – no issues until now.
So, here's the current problem: My AC blows cold, but on hot days, if the fan is on high, it'll cut out for a split second then kick right back on. It also does this when I use a window switch to roll up a window, like if there's too much power being drawn. I haven't specifically tested it with other things running besides the AC. Also, one of my headlight bulbs went out recently.
I've already tested the blower motor by itself, and it runs fine. When I replaced the resistor months ago, I also checked the connections from the dash, and they seemed good. I did leave the sunroof open in the rain once almost four years ago, but it dried out fine, so I'm not sure if that's even related to this.
It's not super urgent, but I just can't use the blower on high without it acting up.
Edit: Oh, I forgot to mention, I'm using an aftermarket refurbished alternator. When I tested the battery with a multimeter, both under load and without load, I was consistently getting high readings, around 14.8V.

 

[Doubeleive]

Sounds like a ground or power issue somewhere, start at the battery.