2-wheel Drive Light Indicator

[Max Hoepli]

Happy New Year All!

I have a 1986 Audi Quattro, when turning the knob for 2-wheel drive the green indicator light does not go in the axle symbol for the front wheels, when turning to 4-wheel drive the green light dot luminates on the symbol on the rear axle between 2 rear wheels. Why won't green light dot illuminate on symbol between 2 front wheels?
Last time in November when used both green dot lights were illuminating.


Max