No brake lights

I have a Pleasure Way Excel TS mounted on a Ford E350 Wide Body Chassis. I have no brake lights on both lower lights as well as the upper third light. All other lights work fine. Turn signals, running lights, hazard lights, backup lights all in good working condition. Checked fuse under dash and under hood, working. Checked and replaced brake light switch. Test light shows power at all times to one side and both terminals while depressing the brake. Opened up passenger side rear light assembly and checked all connections with grounded test light. No power to brake light terminal. Looked at bulbs in third light. All appear to be okay, but did not replace. Connections seemed to be okay. Any advice?