What is causing the dash lights to go out and come back on occasionally? on 2000 Ford Focus

When the left side goes out - the heater controls, gear shifter and radio controls also go out. The left side went out first. Then the right side. The left side will come on sometimes along with all the other control knob lights. The right side of the dash ( instument) lights doesn't come back on.

Asked by for the 2000 Ford Focus
sounds like a loose connection somewhere.probably at the back of the instrument cluster