Cessna Autopilot strange behaviour

Hi all,

I'm quite new on the forum so, first of all, let me write a couple of lines of presentation.

My Name is Alfredo, I'm from Italy, I'm 48 and since 2011 I hold a PPL in the real world .

I'm new to xplane, I just bought the 10.0 global version, anyway I'm quite familiar with FlightSimulator X.

After few hours of flight using the Cessna C172 in Xplane, where I used the autopilot with no problem at all, now I'm not anymore able to engagé the HDG mode.

If I click on HDG nothing happen or maybe it get lighted for few milliseconds and immediately turn off.

If I do the same while Xplane is paused, seems all fine and the HDG indicator is lighted, but when I remove the pause, HDG light switches off.

If I engage the autopilot the plane turn viloently to the right loosing the asset and, if no action is taken, it crash to the ground in few second or a minute depending obviously by the altitude.

Do you have any idea about the cause of this strange behaviour?

Thanks in advance for any info.

Ciao.

Alfredo