Crazy headlight problem

[Kerndogg]

Recently my headlights started acting weird. 03 7.3 CC 4x4 Lariat. It has the auto headlights that were working fine. One night got in it to go somewhere and the auto headlights would not work, turned them to the on position and they would still not come on. I turned them back to the park position and the low beams come on? Back to off and the marker lights come on. After messing with them. Here is the breakdown.

Auto-headlights on when daylight, nothing when dark.
Off-marker lights on
Park- marker and low beams
On- marker lights only
The brights will not activate on any setting but the flash to pass still works.

I have already ruled out the headlight switch, I tried a buddies with the same result. The turn signal switch seems to be working just fine. Any ideas?

[Kerndogg]

Anybody? Surely I can't be the only one with this problem?

[Kerndogg]

No help? Somebody give me an idea? Do these have a module?

[mcyrana]

check fuse 7, 14, 27

the auto lights sensor also runs though a microprocessor in your VSM

[Johnsabine2003]

are the lights as bright as they normally are? if not you could have a grounding problem in the headlight circuit.


Sent from my Autoguide iPhone app

[Kerndogg]

Originally Posted by Johnsabine2003

are the lights as bright as they normally are? if not you could have a grounding problem in the headlight circuit.


Sent from my Autoguide iPhone app

The lights have always sucked so hard to say. Where abouts would the grounds be? I already checked fuses and they are good. Thanks for the ideas.

[Turbostang500]

Im gonna say ground.
not sure where they are located though. Check up around each headlight and under your dash.

[Johnsabine2003]

Pull a headlight and start tracking there. A problem I've seen with a lot of fords since about 2000 is that owners put high wattage headlight bulbs in and melt the headlight sockets or burn up the wiring, often resulting in a grounding issue. I had actually forgotten this issue till I read your post again. The damage is usually obvious. If this is the case you can usually find replacement headlight harnesses at autozone.


Typed with my thumbs from my Autoguide app.

[Kerndogg]

Does anyone know what the .3 ohm resistor is for bolted behind the ds headlight? Mine is showing .4 on my meter and it says tolerance is 5% on the resistor. Think the resistor is no good or maybe my meter isn't going down accurate enough? Is it part of the headlight circuit?

[mcyrana]

Theres a resistor in the driver side headlight to dim ot a little bit to not blind drivers on the other side of the road.

I dont know if you have ever noticed that the passenger side headlight is on some cars are brighter than the driver side