1991 Jeep Wrangler BRAKE LIGHTS

I am having almost the exact problem on my hot rod. The brakes lights were working fine. I cut the brake light wire to add a new 3rd brake light. Nothing worked.

I reconnected the cut wire - nothing.

I connected a voltmeter into the wire and grounded the common side of the voltmeter -- no volts to the light.

This happened one other time when I disconnected the old non working 3rd brake light. I reconnected the brake light wire and NOTHING.

A day later while I was thinking about it, it worked and has been up until today.

I know you will tell me to wait for the magic to work, but this is a safety issue and I want to fix it right.