I set a FIX way point and then flew a heading away from the location of the FIX. When I turned on the NAV ir immediately captured the FIX but 180 out. I had to hit the BC button to get the NAV to track the fix point. When I switched to track an NDB or VOR it worked fine. In he above situation I had set the proper frequency for an ILS landing at KGGG. When I thought it should have captured the localizer and it did not I checked the frequency and both the one in the VLOC and the one in NAV 1 had changed. after changing the frequency setting the system captured as it should except the G/S. The plane flew right over the airport at the altitude it had been flying at. the G/S bug was sitting right on the mark like it was on G/S.