I had my headlights/foglights go out on me the other night. I am going to replace my bulbs, but I wanted to vheck the fuses first to make sure. Which one (s) should I check first, there are about 4 different ones for the lights. If it matters the parking lamps still work fine. This is on a 2004 NBS

 

Umm, have you looked in your owner's manual for the fuse information?

 

Yes i have. There are about 4 or 5 different fuses for the lights. There is a LH low beam, RH low beam, bright lights and one for low beams. Just didn't know which would be most beneficial to start with.

 

You may have lost F35, since it seems to supply both the headlights and the fog lights. Others to check are F25 and F23, F40, F6 and F17. I understand your dilemma - the system seems to have been designed by an Italian chef cooking spaghetti.

- Jack

 

What do you mean by f35? All it says in the owners manual is listed out in a numbered diagram, but no letters before the numbers??

 

I checked all the fuses and they are all good, so I guess the problem is the bulbs. But i still dont understand bc I replaced the fogs already and they wont come on???

 

Oh yea, I forgot to mention when i turn the lights on the hi beam indicator stays lit whether I put the brights on or not??

 

Sorry my friend, I was looking at a Chilton's wiring diagram and that's how they show them. F35 is fuse # 35. All the others are similar. Just ignore the "F's".

Edit: If you've checked all those fuses and they are good, then I'm stumped - sorry! (Wish I was a real expert - then you could pay me for my advice).

If it's not the fuses and not the bulbs, then it has to be the switch or the wiring, doesn't it? And, I don't have a clue what to tell you to look at first.

- Jack

 

I havent changed out the headlight bulbs, just the fogs so I'm not sure if that matters?? I am waiting on the headlights to come in. I figured since they all went out at once it might be a fuse, but im stumped.

 

The probability that all headlight and fog-light bulbs would fail at the same time is so low that it's next to impossible. Replacing them instead of diagnosing the actual fault is going to do little more that waste your time and money and you will still have the same fault when you're done (but you will have shiny new bulbs that still don't work).

Point to note: The circuit is designed so that the fogs CANNOT come on when the high beams are on. If the high-beam indicator is on, that tells me the high-beam circuit is hot from the main light switch, locking out the fogs.

Need more information since we're missing specifics:

Do either low beams work in any MFS (multifunction switch) position?

Do the high beams work in any MFS position including the flash-to-pass?

Does the instrument panel illumination circuit work when the lights are switched on?

Does the "FOG" indicator light up when the fogs are turned on?

Is the truck equipped with DRL (Daytime Running Lights)? If so, do they work?

Is the truck equipped with the "auto-lamp" feature?

Precise answers (a yes or no is sufficient) to all of those questions and any additional observations you may make will help pin down the faulty part of the circuit.

 

the actual pigtails burned out on me on my 06 F-150. the drivers side one burned out first, the pigtail connector where the light plugs into the harness was melted. then a few weeks later the passenger side bulb melted and wrecked my fog light assembly and the pigtail.

You might want to check your pigtails and see if they are melted or deformed at all... that maybe a part of your problem.

 

Let me ask 2 dumb questions in addition to projectSHO89's questions.

1. Do you have HIDs installed ?
- I did a quick search on your Member name and HID, and found 4 threads, could just be text in the posts from other members. I did not open any of the threads to read them.

2. Do you have a meter ?

 

Bonus points to anyone who can explain COMPLETELY how the fog lamp relay is energized and how it is disabled when the high beams are on.

Took me 45 minutes of going through the diagrams before it dawned on me how they did it....

Send me your ideas by PM so we don't ruin the fun for a while. I'll keep track post them all later.

 

Maybe this would answer it completely ?

https://www.f150online.com/forums/el...aybe-04-a.html

 

Ah, c'mon. Six minutes! Ya took the fun out of it! I scratched my head for awhile looking at the schematics to figure that out!