No power to low beams at the headlight.
No power to lowbeams when jumper is on sockets 4 & 5 on the black plug behind the headlight switch.
New MFS.
Highbeams and flash to pass work, as well as every other control on the MFS.
Currenly with HIDs, which will go away as soon as I can get power to the low beams.

 

Check fuses 7&8 in main power distribution box (hot at all times)
Check fuses 26&28 in fuse relay panel (hot in run position)

 

All fuses are good. I guess I should mentioend that!

 

But do you have power across the fuses? That will help to find where the power interrupt is occurring.

The left headlamp power flow is :
fuse 8 -->DK BLU/ORG WIRE-->Main light switch--> RED/YEL WIRE-->MFS
MFS- -> RED/BLK WIRE -- Fuse 28 --> DK BLU/WHT WIRE-->Left headlamp

If you have power everywhere then maybe the bulbs are burned out in the low beam filament.

 

Will test the flow, but as for the filament--there are two wires going into each HID controller. When in high beam I get voltage. When set to low beam, I get nothing. If you tell me that there should be MORE wires going to the headlights, I just might cry.

 

There is a second wire going to each headlamp. A LTGRN/BLK WIRE which is shared between the two headlamps. That wire goes back to fuse 16, in the fuse relay panel, then a GRY/ORG WIRE from the fuse 16 back to the MFS. I presume it is for the hi-beam.

 

I DO NOT KNOW WHY. IF SOMEONE CAN EXPLAIN THIS, I WILL BE EXTREMELY GRATEFUL.

Low beams don't work on the truck. Highbeams, yes. Low beams, no.

What it can be: headlight switch, MFS, fuses, relay, wiring, or any combination thereof. Side note: I despise wiring issues.

After a week of troubleshooting, I decided that it is NOT a power issue or a switch issue. It is a WIRING issue. Did i mention I despise tracing wiring? In a loom? Or sheathing? I situate myself behind the right headlight, and flash my light down there.

30 seconds in: Why are there two wires with ring terminals not connected to anything? I know that they have nothing to do with the battery because 1) that wouldn't make any sense, and 2) they don't reach the battery. So, I grabbed some wires and jerryrogged these wires...and my right headlight came on. I tested the switches and everything is good! The low beam comes on with the switch in the ON position and turns off when it is in OFF or PARK. Turn on the high beams and they work. The low beam stays on when the high beam is on but they are separate bulbs and I can live with that.

I do not know why the low beams are deliberately disconnected. But now I need to figure out where the wires for the LEFT low-beam bulb are!

 

Besides the wiring and the switch
You will need to read this for yourself as it would take a page to explain
There are 3 things that fail in HID systems
1 The bulb
2 The ballast
3 The ignitor
There is a good article online about diagnosing these lights put out by Huntersville Ford
You can swap parts around and see what is causing your issue
Possibly as simple as a low quality bulb
Possibly as expensive as a new ballast or ignitor
Google "why HID headlights fail" and that article will come up

 

I DO NOT KNOW WHY. IF SOMEONE CAN EXPLAIN THIS, I WILL BE EXTREMELY GRATEFUL.
Low beams don't work on the truck. Highbeams, yes. Low beams, no.
What it can be: headlight switch, MFS, fuses, relay, wiring, or any combination thereof. Side note: I despise wiring issues.
After a week of troubleshooting, I decided that it is NOT a power issue or a switch issue. It is a WIRING issue. Did i mention I despise tracing wiring? In a loom? Or sheathing? I situate myself behind the right headlight, and flash my light down there.
30 seconds in: Why are there two wires with ring terminals not connected to anything? I know that they have nothing to do with the battery because 1) that wouldn't make any sense, and 2) they don't reach the battery. So, I grabbed some wires and jerryrogged these wires...and my right headlight came on. I tested the switches and everything is good! The low beam comes on with the switch in the ON position and turns off when it is in OFF or PARK. Turn on the high beams and they work. The low beam stays on when the high beam is on but they are separate bulbs and I can live with that.
I do not know why the low beams are deliberately disconnected. But now I need to figure out where the wires for the LEFT low-beam bulb are!