Electrical issue

Hey chat,
I’ve started having this problem with my 2010 SR5 4Runner that the lights in the car and radio turn off as soon as I turn on the headlights , they work perfectly fine when the headlights are off and the ac works consistently when they are off or on, also the car starts up perfectly, does anyone know what the problem might be?
I haven’t taken to a mechanic yet because I’m not sure if it’s a matter of replacing a fuse or adjusting something, thank you!

 

You probably checked this, but did you ensure the panel dimmer control is adjusted to full brightness?

 

Yes it’s not that :/

 

Nothing was done to the headlights? No aftermarket electrics? Does it happen whether the engine is or isn't running? Have you tried disconnecting one headlight, then the other, then both?

 

Which “lights” are you referring to? When you turn on the headlights the dash and radio/clock displays will dim, as designed. Is that what you are seeing?