The brake lights were always on and the rear running light off. Checked for a short or burnt bulb at the taillights but found none. Moved the wire harness around without success. Pulled off the rubber housings at the front brake light switches and found that two wires to one switch were touching from their being pinched together where the female connections attach to the switch. Thought that was it but the problem re-emerged shortly after reassembly. Removed the switches themselves (they just screw out by gripping the brass barrel, not the plastic prong that separates the male connections). Sprayed PB Blaster into the switches and worked the switch button back and forth several times. Testing the switches I was surprised to find that while the button is pressed in it passes current but when functioning in the brake handle, applying the brake allows the button to move outwards and stop the electric flow. Seems the brake light comes on when the switch is off. Somebody please check me on this. In any event, once reassembled, the brake light works normally as does the running light. Had no luck finding new Brake Light switches for the A3 engined models of Tomos so feel lucky this simple repair cured it.