I repaired shorted wires going to the left rear turn signal. After the repair the left turn signal works great. However, it doesn't operate as a running light. The right turn signal does operate as a running light. My Clymer Repair Manual doesn't say anything about this and the wiring diagram doesn't show anything for the rear running light. By the way, both the left and right rear lights have only two wires and have single filament bulbs. Any suggestions?