Stupid problem. Fuses fine, wires fine, bulbs fine, MFS fine (pulled it out, tested it), cutie next door fine, everything fine - no lo beams.
Solution:
Parking light wire powers relay; relay powers lo beams from battery.
I'd like to thank the Academy.

 

Damn people I just solved a huge problem that's been plagueing this forum and no one even comments!

 

Once again, no need for the potentially offensive language.

This is not a fix, this is a work-around. It's hardly a problem that's been plagueing this forum.... the problem is unique to you, as you should have been able to tell by the responses to your original post about the problem.

20 minutes with a 12V test light would pin down the problem that caused it in the first place. You are either unwilling to heed our advice, or simply unwilling to attempt a proper repair. In either case, do as you see fit; it's your truck.

If the fuses, switch, wires, and bulb were all fine as you stated, the lights would work fine too. They don't. Did you so much as check for power at the socket with a test light? Did you trace any wires at all? If the switch was working properly, how did you test it? If the switch was working fine, was power getting to it in the first place? Yes, I'm calling your diagnostic techniques into question here.

-Joe

 

Joe, you need a life, for two reasons. One is that if I say damn and you have a cow, then wake up+smell coffee because American swears nowadays. And two, I did all but trace wires. I took a multimeter and theres no power coming to low-beam wires at bulb; I pulled out MFS and tested all of its pins for continuity; I tested power-in bunch of wires going to the MFS and bridged them all with wires in different combinations and nothing happened = switch was fine.

 

I need a life? Whatever. I have one and I'm quite happy with it, but thanks for the suggestion. The next time I'm feeling down and depressed, I'll know that someone cares.

You, however, need to go back and read the terms of use you agreed to when you registered for the forums.
While Americans swear(), this is neither the time nor the forum in which to do so, especially at someone who is attempting to help you fix a problem the right way.

OK, so you checked one connector, and claim to have checked another and the multifuinction switch. I would list the specific wire colors and connections you would need to check, but that would be a waste of time. You don't care what we have to offer and you're going to do it your own way anyways. So you checked one pin on the headlamp harness... Big deal. Start tracing it back to the point where the power stops flowing... it's not rocket science. You have power at the battery, and you don't have power at the light bulb connector. That means that somewhere in between, there is a broken connection or a malfunctioning part. If everything was fine, they would be working fine.

You only need to check two. Why in the world would you check all of them???


Then you didn't check the correct two. Again, there are only two that needed to be bridged. The two Red/Yellow wires would need to be spliced together, one should have power with the main headlight switch on, the other should have power when you jumper it, and at that point, you should have power at both fuses for the left and right low beams.

Your test method does not add up to this conclusion.

I guarantee that if you had power at the fuse box, but not at the light, you have either a bad wire or a bad component. Your diagnostics have not conclusively determined anything, and your repair hasn't fixed a thing, other than the fact that they make the lights come on now...

Fine... Whatever....

 

I like how it became "a huge problem that's been plagueing this forum" all of a sudden.

I will second Joe's comment, all you did it rig it so the low beams worked again, you did not provide a soultion to anything.

In your thread I asked several problem diagnoses questions about power in the fuse sockets. If you would have taken the time to pull the low beam fuses, turn the headlights on, in the low position, and checked the fuse socket with a meter, you would have know if you needed to go towards the lights or towards the MFS, to find the problem.

You checked the MFS...with what procedure ? Did you just start placing a meter over some leads, and see what happened, thinking you found the low / high beam contacts? You provided no detail to the steps you took.

I find it quite commical that you don't do any problem diags, and shake some wires as a problem determination step, then complain that no other member felt the need to reply to a duct tape type repair job.

Hope you did the relay work correctly, and your truck does not catch on fire. Insurance company will tell you to pay for it yourself if it goes up in flames.