Dash Gremlins - Electrical

interesting... I guess I never mentioned which vehicle this is for. But it is a 68 Dart Convertible with the slant six.

I can check the bulkhead connector, but why would all of a sudden the bulkhead connector get a bad connection within a couple months? I did not touch any of those connections last year or this year. The only storage difference between this past winter and other winters is this past one I had the car stored at my house here in pittsburgh PA and the winters before were spent in a barn back in lancaster PA. Both have the same climate during the winter. I dont believe the temp difference in the storage area (if any) would affect the bulkhead connector... would it?