I have a 2004 f-150 xlt and need some help testing the headlight switch to see if it is bad. i have a multimeter but suck at using it. Can anyone help with pictures or testing to see if its bad or not.

My trucks tail lights parking lights and dash lights do not work and i have no fuses blown. My fog lights only come on with the high beams. When i turn my fog light off a white light flashes on then off.Any help would be great.

 

If you have a 2004 Heritage, the, main headlamps switch test diagrams are here :
https://www.f150online.com/forums/me...9-2003-my.html

If you have a 2004 New Body style truck, they are here :
https://www.f150online.com/forums/me...4-2008-my.html

 

i dont really know how to read the diagrams is there any way you could pull out your headlight switch and take pictures of how to test it or what ohms levels should be on witch wires cause i dont really know sorry to be a pain but it would really help me out.

 

This is the diagram you need (got from the link above, assuming you have an NBS truck).



Pull the headlight switch out, disconnect the wire connector, and look for the connector that looks like the one in the diagram (one with 10 pins).

Put the multimeter in the mode selected in green (continuity test, it'll make a beeping sound if you touch the multimeter leads together).


If you want to test the headlights, for example, you touch the leads to pins 6 and 1 (match them up with what the diagram shows.) If the dial is in the Auto, Off, or Park settings, the multimeter won't make a sound. If it's in the headlight setting, the multimeter should beep (and I think it will display a number close to 0?)

If you want to test the parking lamp function, connect the leads to pins 10 and 5 (the ones all the way on the right.) The multimeter will be silent if the switch is set to Auto or Off, and it will beep if it's in the Parking lamp or headlight setting.

And so on and so forth. Hopefully I described it well enough

 

Thank you very much scully and thank you elvato. Im a tard when it comes to electrical but, you made it very easy to undertstand. Im going out to test the switch now thanks this is exactly what i needed

 

The only problem is mine has 12 pins and 11 wires for some reason the one in the diagram has 10. Hmm now what do i do? its a new body style 2004 xlt with 4x4 this sucks lol. I need to get the truck inspected and need to figure this out.

 

Great diagram and description. Which of the pins is a 'ground'? or is there no common 'ground' pin?

Also, are ANY of these wires a 'switched power' wire?

I am looking for a switched power wire somewhere in this area of the dash to connect to my extra fog light rocker switch [yes, it is a relayed system] so that the extra fog lights lose power when either the key is out or the headlight switch is not turned to at least the park position.

Thanks.

 

There is not a ground associated with the headlamp circuits. There is one for the instrument illumination. Just take the ground wire down the driver's side kick panel to ground there.


The parking lamp circuit is a switched power, it is the brown wire at the back of the main headlamp switch.

 

Thanks again [as I said on the other thread]

Sorry for high-jacking this thread.


UPDATE: They work fine with that wire. thanks again!