Not sure this is in the right subject area. The tach is made by Horizon instruments. I have it installed on my Turbo Arrow IV. Yesterday during a 3 hour X country about midway in stable cruise flight at 11000ft the left magneto status signal red light came on for about 2 minutes. Apparently it should turn on when there is a loss of signal from the Magneto. I had no RPM drop and after two minutes light went out. On landing did a mag check - all normal. What could cause a signal loss for about two minutes?