Where is the daytime running light module on a 99 Ford Ranger?

There isn't a separate "daytime running light module" in the sense of a dedicated box or component on a 1999 Ford Ranger. The DRL functionality is integrated into the vehicle's existing electrical system and controlled by the body control module (BCM) or possibly the headlight switch itself, depending on the specific configuration of your Ranger.

To troubleshoot DRL issues, you'd be looking at:

* Body Control Module (BCM): This is the primary controller. A faulty BCM could prevent DRL operation. It's usually located under the dashboard, often near the steering column.

* Headlight Switch: A malfunctioning headlight switch could also interrupt the DRL circuit.

* Wiring and Fuses: Check the wiring harness leading to the headlights and related components for damage or loose connections. Consult your owner's manual to locate the fuses related to headlights and daytime running lights.

* Headlight Bulbs: While seemingly obvious, ensure your headlight bulbs are properly functioning. If a bulb is burned out, the DRLs might not function, depending on the system design.

In short, there's no single module to replace. Diagnosing a DRL problem in a '99 Ranger requires a more systematic approach, checking the items listed above. A wiring diagram specific to your year and trim level of Ranger would be very helpful for this troubleshooting. You can often find these online through auto parts websites or repair manuals.