98 Sunfire, brake faults

This is for a buddy of mine here in this area. Her Sunfire had rusted-out brake fittings on the dummy rear axle. Now that those fittings were replaced, she's now getting some kind of electrical/electronic fault. The idiot lights will illuminate by themselves for seemingly no reason, then will self-terminate for some unknown reason. There are no known electrical faults, no other electrical malfunction, though the ABS light does illuminate with the e-brake and Brake lights. I'm thinking possibly old hubs, but what yall thinkin? Thanks, fellas!