Sounds like “Cockpit Interaction System” setting.
Go to “General Options” → “Accessibility” → “Cockpit Interaction System”
What is it set at? Make sure it’s on “Legacy”
Then you should be able to put your mouse cursor just above the knob to ‘push’ it and just below the knob to ‘pull’ it. Your cursor will change to an up arrow or down arrow when you hover to indicate what happens when you press the button.