Can you test continuity on the actual pad? Like there should be two parts to it that the carbon pad bridges. And also, you might want to try cleaning it with some flux and then isopropyl alchohol, or even just the alcohol and a cotton swab. It sounds like it might be oxidised.
The other thing I would say, is sometimes you have continuity but a trace is damaged enough that it can't supply a needed voltage. In this case though, the voltage needed would be so low, I doubt that would affect anything.