4x4 light coming on when 4x4 not engaged
 

1996 Toyota 4runner auto transmission, 4x4 shifter, not button.

When I come to a stop in 2HI the 4 wheel drive light starts to flicker, and if I'm idling it'll flicker as well. When I decelerate at low speeds to a stop, I hear a loud clunk coming from the front of the car I believe it's 4x4 engaging. Any tips would be really useful!

It might be useful to ***CAREFULLY*** observe if the front driveshaft is rotating when that clunk is happening.

The light flickering could be something a simple as a wire rubbing against something, or a flaky switch on the front diff.

If it's actually engaging/semi-engaging the ADD unit on the front diff it's a bit more involved.