Today I lost the running lights on my 89 F150, I have headlights, brake lights, and turn signals, but I have no dash lights, no front or rear running lights. I checked the fuses under the dash and didnt find any blown ones. Are there any fuses somewhere else? Anyone have a wiring diagram for the lighting system? I want to trace this out as well as test my headlight switch before I replace it. Any suggestions?

 

From 88 manual, fuse #4 in dash panel should supply parking lights and dash lights thru the main light switch (headlight switch). Lead coming from headlight switch should be a brown leadand supplies all lights you refer to. Lead coming from fuse #4 id a tan/white lead to the headlight switch.
Hope this helps.

 

Thanks! Turned out to be a bad connection at the connector that snaps onto the headlight switch, the plastic looks pretty brittle but all is good now. Thanks again.