Suddenly, the headlights on my '99 F-150 are always on, even after I turn off the engine and remove the key! I can still use the dashboard light switch to torun off/on the parking lights, but the headlights are always lit. This problem was preceeded by a small buzzing sound coming from the fuse box beneath the driver's side dash.

Could this be a problem with the daytime running lights "relay"? Has anyone had this problem before?

Jeff

 

Hi Jeff and welcome to FTE

Maybe the problem is that your truck knows that you like Isuzus and it's insulted?
Ok never mind

Is your truck a Canadian model that had daytime running lights? If not then it shouldn't have a DRL relay.
Does it make any difference whether it's raining or not? If you have a leaky windshield and water get's into the fusebox it can cause the problem. The buzzing could be the water shorting between the terminals inside.

 

Thanks for the welcome, Racerguy! Don't hold my screen name against me -- it's a holdover from when I owned an Isuzu Trooper. I continue to use it for all my web accounts because it and my accompanying password are easy for me to remember. Hopefully, my F-150 doesn't regularly read this forum and thus won't discover my formal loyalties. ;o)

No, my lights problem is independent of the rain. And I'm not sure if the truck is a Canadian model as I bought it used in San Diego. It's possible, but I don't know for sure. I checked my owner's manual and it shows (and I verified) a daytime running light (DRL) relay in the fuse panel to the left of the driver's knee.

Here's how the problem unfolded:

-- Driving down the road one evening and I heard buzzing sounds from beneath the dash, lasting a couple seconds. No obvious affect on the headlights at that time.

-- When I reached my destination I turned off the ignition and turned off the dash light switch. Although the parking lights went off as they should, the headlights remained on. I fiddled with the dash switch and suddenly the headlights went off.

-- The next morning, I fired up the truck no problem and the headlights came on, as normal, in DRL mode. Drove the truck to my destination, but once again the headlights did not turn off after I stopped the engine. This time I couldn't turn them off by fiddling with the dash switch so I removed the two headlight fuses.

This is the state of things today. Until I get this sorted out I have to insert and remove the two 10amp fuses everytime I want to use the headlights. I don't think the problem lies with the dash switch because the parking lights respond when I turn them on/off. And because the lights remain on even when the vehicle is off, I assume that the issue must lie in the mechanism that automatically turns off the lights when the ignition power is cut. That's why I suspect the DRL relay. Might there be another culprit?

Jeff

 

Removing the DRL relay would be an easy thing to try. It might be as simple as needing a new relay.