Did you check the fuses in both the Battery Junction and Central Junction Boxes? Fuse 4 (mini amp) in the BJB and Fuses 11, 27 and 33 in the CJB all supply power in one way or another to the Daytime Running Lights.
I would start by checking the fuses - here is the Forum's "How To" on that subject.
If you have a Canadian vehicle it is also possible that your Daytime Running Light Module has failed and needs to be replaced. If I recall correctly, it is located on the left hand front corner of the engine compartment.
Some of the symptoms of a failed DRL module include: Dim or no daytime running lights, full high beams at all times or just with the key on, headlamps flashing.
I am attaching a DRL troubleshooting file for reference - I understand it is not specifically for a 1999 Ranger, but it is for Canadian vehicles, if yours is.