I have a 2001 F150 with the auto lamp and fog light option. I have done the fog light mod to it as well (I did this well over a year ago with no problems until today).

Today I noticed my headlights were on when I was supposed to have only my park and fog lights on. Upon further inspection I found it was ONLY my headlights on; no fogs, parking lights, or tail lights as well as the dash lights were un-illuminated as if my switch was in the 'off' position.

I found the #6 fuse under the hood to be blown (main light switch, park lamp relay) as well as the #27 fuse under the dash to be blown (fog lamp relay and fog lamp indicator, main light switch (upstream)). I replaced the two fuses with correct sized fuses and everything was fixed.

I drove a few miles and the same problem happened. When the lights shut off I heard a pop (like a fuse blew) from the head light switch. So I replaced the fuses again but I accidentally put a 25 amp fuse in place of the 5 amp under the dash, and my headlights would come on when I switched it to the park lamp setting. I put the 5 amp in and the lights worked as they should. I drove again just to see what would happen and again the fuses blew.

I replaced the under hood fuse and kept fuse from under the dash OUT, and things worked as they should. I drove a home this way and just had the park and head lights on, no fogs. I had no issues on the way home.

When I got home I pulled the switch from the dash with and tapped it and gave it a good shake to see if maybe a short was in the switch. I also drove over a bumpy road with just my fogs and park lights on and nothing happened.

Does anybody know where I could start troubleshooting this? I'm going to borrow a different switch tomorrow and try that out, but I doubt it's going to be this since I messed around with my factory switch.

Sorry for the long post and thank you in advance for ANY help.

Mickey

 

Intermitant electrical problems are some of the toughest problems to locate. My guess would be, that you have a wire somewhere that has the insulation rubbed off, or pinched to gound.
I would post this in the electrical forum also. Some people don't scour the whole site. But there are some guys that do the electrical, that don't always make it into this forum.

Good luck

 

Thanks Tumba.

If a moderator sees this, will they move it to the electrical forum?

Thank you.

Mickey

 

I'm not sure, I would go ahead and open one there. Then I'd just subscrib to both. There may be someone here that has had the problem also.

 

I take it by the description that when you did the fog lamp switch mod, you did the physical ramp as well as changing the source for the power to the fog lamp relay ( did I read that correctly ) ?

This is what the wiring looks like now



The reason I ask is BJB ( Battery Junction Box aka Engine compartment fuse panel ) Fuse #6 is both for the Park Lamp relay for the autolamps, as well as the main headlamp switch for the parking lamps when turned to the park or on position. BJB Fuse #3 is what drives the headlamps via the MFS.

If you want to try a test, remove CJB ( Central Junction box ) fuse # 27. This is not needed if you changed the fog lamp switch power to the brown wire ( parking lamps ), and actually could be the source of the flow of power to the headlamps.
CJB Fuse #27 is what powers the fog lamp relay, and is fed from the MFS in the low beam position. This is how the factory function of turning the fog lamps off when the high beams are on is done.

If you have power from the parking lamps fed back through the MFS to the low beams, this is why the 5A fuse kept blowing, as well as the parking lamp fuse, BJB Fuse #6 ( trying to drive the fog lamp relay, along with 2 55W lights ). This is a 15A fuse feeding a 5A fuse, trying to drive what normally has 2 10A fuses on it.

Remove CJB Fuse #27, and see if the problem goes away.

One other question, do you have DRLs as well ?

EDIT : We do not move threads like this around, unless requested by the member.

 

Yes, I jumped the brown wire with a dark colored wire (black maybe?) with a white stripe. No I do not have DRLs.

I currently do not have a fuse in the #27 location and things seem to be working just fine, I ran my fog/park lights without a problem earlier.

With the fog light mod, are you supposed to remove the #27? I do not remember that being in the instructions.

Thanks SCULLY.

Mickey

 

It is not good to have it in there, sure the directions do not make note of it.

I would always point out to remove that fuse, just makes sense to remove it.

As you found out, this does give a path to the headlamps, and can cause all sorts of strange problems.
Not sure how it has worked well for so many without removing it.

 

Well, I'm going to bring this thread back from the dead because I'm still having the same problem and I'm hoping for some more insight as I have another clue to the puzzle.

I decided that the trouble that I was experiencing with blowing the #6 fuse under the hood wasn't worth keeping, so I reversed the fog light mod about a year ago and returned the wiring back to stock.

Well, I'm STILL blowing the fuse. I have looked over the wiring behind the headlight switch and things there look fine, I put electrical tape around the insulation from the wiring splice I did for the mod.

I was adjusting my pedals a few days ago and the 15A #6 fuse in the battery junction box blew. I have decided now that I may have a problem with the wiring in the pedals rather than, what used to be, my fog light modification. I can see the wiring for the pedal switch is wrapped with the headlight wiring connector, but I don't know the best way to follow it to see how it is tied into the headlight switch which would cause it to blow the fuse.

Does anybody have an idea as to how the pedals are tied into the headlight fuse under the dash?

ANY help is appreciated, greatly!

Thanks,

Mickey

 

SSCULLY? Anybody?

Mickey