2002 Explorer DRL (daytime running lights) pulsating

[jonyrotn]

I have a 2002 Ford Explorer XLT 4.6L v8. I have just recently noticed that the daytime running lights are pulating when the vehicle is running. Just wondering if this is a headlight module problem or if there is something more serious going on such as an electrical issue.??

[shorod]

Does the pulsation continue if you turn on the "regular" headlights?

-Rod

[jonyrotn]

no they dont. when the headlights are turned to the on position the pulsating stops.

JD.

[shorod]

From what I can tell from a quick look at the factory wiring diagram, the DRL module provides power to the headlights on a parallel path from the regular headlight circuit. I'd suspect the culprit is the DRL module. You might try checking the voltage from the DRL module to the headlights to determine if the pulsation is there.

Someone hasn't attempted to install HID headlights on this truck, have that? Or maybe a previous owner was a cyclist that understands pulsating lights improves visibility and they installed an oscillator as a DRL circuit.

-Rod

[jonyrotn]

no, no one has tried to install the HID lights. i have owned this suv for 6 years. It just started doing this 3 days ago when my wife was backing out of our driveway. I thought she was flashing the lights.

Thanks for looking into this Rod.
From your wiring diagram, what colour of wire should I be checking the power from the DRL module, and should it be 12v.

[shorod]

The power from the DRL module to the headlights is a Red/Black wire at pin 1 which connects to the low beam of each headlamps (splice #S117)on the source side of the 10A headlamp fuses in the Battery Junction Box (F1.42 and F1.43). Power to the DRL module comes from fuse 1.28 (10A) in the Battery Junction Box and fuse 2.30 (5A) in the Central Junction Box. Fuse 1.28 only provides power to the DRL module so you should be able to remove that fuse to disable the DRL system to confirm the issue lies in that module.

-Rod

[jonyrotn]

I will check it out. I was searching the web and it looks like a common problem with the explorer and other vehicles.

[jonyrotn]

my apologizes for not replying sooner....been away for sometime. Just got back to fix the Explorer. Yes it was the DRL module causing my lights to pulsate. i replaced the DRL module that is located on driverside inner fenderwell near the firewall.

cheers. Jonyrotn.