Not even after you take off? My Yaw Damper lights goes off once I have taken off. But until then, it remains on.

I would surmise that the yaw damper is cut out on the ground to keep it from over reacting to rudder inputs. Once weight is off the gear, it is activated if the switch was ON.

Yaw dampers are strange things. I flew the good ole' Grumman F9F-8 Cougar, the first USN jet to have them (2 - for redundancy). She really needed them in the landing pattern!

One of the taxi checks before takeoff was to momentarily turn them on, kick the rudder pedals and see if the dampers kicked back at you - (they should). You then turned them off for the rest of taxiing and takeoff. Otherwise, they would go crazy with trying to taxiing or take off using any rudder or differential braking.

Many early tactical military jets did not have nose wheel steering and used differential braking until the rudder became effective.

This is a guess, but I think I am on the right track

I based my guess on the fact that after trying a couple of things on my installation, I found this:

1. On the ground, YD switch on, light on
2. Leaving the YD switch on, after takeoff, the light goes out.
3. airborne, cycling the switch on and off causes the light to cycle with switch position

my Yaw damper light stays on until after take off