Got a 89 240 DL, the taillights have been on the fritz for awhile. Ordered new circuit boards and installed them, no such luck. All the lights work fine except for the running light. Brake lights and turn signals are fine.

Does anyone have any idea as to what is causing both running lights to not work? Or does anyone have a service manual and could tell me the color of the wire that runs to the running light and where it originates?