Good morning. Thanks in advance for the response.

I have a 2003 4th gen 4runner. Stock headlight setup.
The issue:
When my headlights are in the on position set to low beam - no issues.
If I snap the light stick forward into the bright position the bright lights do not power on, the fog lights do turn off as expected.
If I pull the stick back into the manual bright position (where you have to hold the stick back), the bright lights will power up and work great.

Some diagnosis:
When the low beams are powered both sockets on either plug show 12v powered on.
When the high beams are powered on one socket turns to ground while the other is at 12v. This is the case on both bright light plugs.
All fuses are in place and good.
Both bulbs are good (and new) (rated at 9 OHMs resistance)
I've attempted multiple good bulbs.

The main question:
What would be causing my bright lights to power on in manual mode on the stick (Pulled back) but not power on when the stick is in the forward position?