I am having a problem:

My low beams don't work but high beams do. There is no current going to the low beams, because they are wired to aux lights from low-beam wires, that don't work either. (Everything worked just fine for months until a 400-mile desert trip).

Another sex of aux lights, that goes straight from battery to fuse to lights doesn't work, either. Fuse is fine. These have a switch with a little light on it; light works.

High beams work fine.

WTF?

 

If it is a 97-03 Truck, pull up the oval on the passengers side dash and make sure that the connector in the middle of the oval is connected, I think I have a picture of it in my gallery

 

We need a little more info. Year, make, and model would be a good start.

Also, we need a better description of the way you have the auxiliary lights connected to the factory lights.

-Joe

 

F150 Screw 2002 XLT V8 4.6L 2x4 truck

I have two sets of aux lights. Rectangular ones on the grille guard and round ones behind the plastic grille in front of the radiator.

Rect: A wire goes from the lo-beam lights to the relay that connects a wire from the battery to the rect lights. Result: turning on lobeams turns on the rect lights.

Round: The round lights are independent from others and have their own switch, which is stuck to the dashboard (wires go through a hole in the firewall). The live wire goes from the battery to a separate relay, and to a switch. The switch turns on the relay, that turns on the round lights.

 

Few questions ( don't know if you did any of this ) :

Q1. Did you check the Central Junction Box ( pass compartment ) for fuses #26 & #28 each 10 AMPs ?

Q2. Did you check the Battery Junction Box ( under the hood ) for fuse #3 30 AMPs ? I would suspect this to be good and functioning, as the high beams both are working.

Q3. Do you have any problems with the turn signals or brake lamps ?
Q3.1. I ask this, to start to check if there might be the start of a MFS problem.

If you look at the following diagrams, you will see that the BJB fuse #3 30 A feeds the MFS which directly feeds CJB Fuses #26 & #28, no relay, so the full current is via the MFS. The high beam activates CJB fuse # 16, 20 AMPs, to power both the high beam elements.





You can pull either of the CJB fuses #26 or #28, and see if power is on either of the pins, when the MFS is in the low beam postion, and the main headlamp switch is on. If not, and the high beams are working correctly, next is checking the MFS ( Multifunction switch aka turn signal lever ) for problems.

The problems with the MFS can be a bad connection under the steering wheel column, either partically unplugged or dirty / bent pins, causing no connection. This sometimes will manifest itself as intermitten turn signal functions, or problems with the L & R turn signals, where the CHMSL works fine.

Check the low beam fuses, prior to digging into the MFS connector or switch itself.
If you want to search on Multi Function Switch or Multifunction switch, you wil find quite a few posts on the topic.

good luck, let us know what you find.

Steve

 

Hey hey I'm back. Finally.
All the fuses are fine everywhere.
My turn signals and brake lights are also fine.
What happened before.. when my low-beams sometimes worked and other times didn't, what I'd do sometimes is turn the normal light switch that controls no lights-parking lights-headlights, and sometimes if I'd tap it or move it harder they'd go on and other times wouldn't.
One time I just moved the wires around under the hood, there's a bunch of wires for various aux lights, and it worked briefly, and then, again, inexplicably, stopped working. It being the low beams.

I can check the MFS (is that the light switch?), I suppose.
I wonder if it's a bad connection to something under the hood, like something not being grounded or whatever. Could a lack of ground somewhere affect it?

 

If you are moving "a bunch of wires for various aux lights" and they start working, the first step is to isolate the aux lights from the system ( i.e. remove the wiring ) to remove one other place for the problem.

I don't know why moving a bunch of wires for various aux lights, would have an impact on the headlamps, if the aux lights we installed correctly.

That is the first step, that I can see. Checking anything else at this point is a waste of time.

 

I removed all of the aux wiring and that didnt do shit for low beams so I'm gonna bridge low- and high-beams at the bulb, so that high-beam wires activate low-beam lightbulbs.

 

OK, first of all, there's no need for that type of language as this is a family place.

Now, the next thing to do is to start chasing power with a 12v test light or a multimeter. Check for power at both fuses, then into and out of the headlamp switch, then into and out of the multifunction switch, then through the firewall and down to the headlights. Being that jiggling the wires that were tied into the fog lights made them flicker, I'd start there. Check both sides of the connections to make sure that the headlight feed didn't get severed when you made the connection.

Finally, you can't just bridge the high beams to the low beams. You would have to physically disconnect the low beams and connect them to the high beam filament. It'll get the low beams back on, but is not the right fix for the problem. Troubleshooting it is not difficult. With a 12V test light, you should be able to narrow down the problem in about 20 minutes. You just need to see where the power stops flowing.

-Joe

 

Joe,

Hang it up. I gave up on this one.
Asked all sorts of questions on the power in and out of fuses and connectors, and I got "All the fuses are fine everywhere", even though that is not the question I asked.

Put the post up about bridging the 2 prior to taking any additional steps in this thread. Obvious that problem diagnoses is not a strong trait of Fordgirl18.

-steve

 

Problem FIIIIIIIIIIIIIIIIIIIIIXED

 

Ditto. Can one of the mods splice all these redundant (and utterly useless) threads together and close them? It's clear that Fordgirl18 just doesn't want our help. Time to cut her off.

 

King shit of piss island, ever heard that saying?

 

Umm, OK... ??? Whatever.... Are you 8? Take a closer look at the terms of use for the site that you agreed to, specifically paragraph 2.

And I prefer 'King Turd of Poop Mountain' myself. None of this has any relevance to the problem. I take it that discussion is done and you've regressed to pointless name calling and swearing just for the sake of swearing?!?! Fine...