My headlights work properly, but flash to pass and high beam do not. MFS seems to be working, when I flash to pass or activate high beams, dash light comes on, but all lights go out when pushing MFS into high beam, or nothing happens when flash to pass. Fuses look good, any suggestions?

 

That sounds like the MFS isn't working. EDIT: I misread, you are saying the dash light is working. Have you checked for power at the bulb or the bulb itself?

 

I don't have a wiring diagram of the '03 handy, but if it's anything like the earlier models, the power goes from the MFS to the fuse and the straight to the blue indicator light and then the "hi beam" connector on the headlight bulb itself. No relays or anything. So, if that's still the case in yours, the blue light going on should indicate that the MFS is operational - or at least somewhat operational. The easiest test, really, would be to pull the bulb connector off the bulb, put a multimeter on it, turn on the high beams and see if anything registers. If you don't have power there, then we can check voltage drop to see if maybe the MFS is working enough to light the light, but can't push the voltage that the bulb needs. Honestly, I have had several cars over the years brought to me with "the headlights don't work" and every one of them have been because both bulbs were just burnt out. The first time, I went nuts with the wiring diagrams and testing harnesses and relays and switches, so I like to start with the easy parts first now

Edit: I assume when you say "all lights go out" you mean that when you push the switch forward you get no low beams and no high beams, but the blue light on the dash is illuminated. That's expected behaviour: On flash-to-pass, it keeps the low beams on, but in high beam mode, it will turn off the low beams.

 

Need more specific information.

Is truck equipped with either (or both) the autolamp feature or DRLs?

What does "or nothing happens when flash to pass." mean?

 

Replaced bulbs already, still no high beams. Yes, pushing the switch forward results in no low beams or high beams. Blue light on dash is illuminated in both cases.

 

I don’t think I have either autolamp or DRLs. What I mean when I say nothing happens is, low beams remain illuminated, but no high beams during flash to pass switching.

 

We know that there is some level of functionality with the MFS since you're getting the indicator light. The fuse should be before the MFS and the indicator in the circuit, so that is likely okay as well (but worth double-checking, really). Looking at the owner's manual, check fuse 7 (30A) and fuse 30 (15A) inside the passenger compartment. It doesn't appear that they added a relay to the system at the factory, so unless someone hacked one in, that shouldn't be a problem. (I wouldn't totally rule out wiring hackery, though, if you're not intimately familiar with the history of the vehicle. Sometimes folks will strap on light bars and wire them through the high beam circuit, and at that point who knows what's going on).

If the fuses are good, I would first check for voltage at the headlight plug and then test for voltage drop. You might also try to measure the amps going across each fuse when you turn the brights on. You can also unplug the MFS and check for resistance across the connectors that the high beam uses. It should be very close to 0 Ohms.

 

 

Ford multi function switch

Mine was doing the same thing. switch turned low beams on, push fwd high beams worked. NO flash to pass. Replaced the MFS and that solved my issue. So you get no hi beams with flash to pass or pushing the lever fwd?

 

He already provided that information as well as replaced the MFS. Please read whole thread.
If the MFS were faulty, the high beam indicator in the cluster would not come on. While almost the same symptom, it's not the same set of symptoms.

 

Where did he state that he replaced the MFS. If I missed that I am sorry

 

My bad, I misread what he wrote. Sorry 'bout that!

 

No worries. Remember the good old days. Simple pull headlights and brights on the floor 😁

 

I do miss brights on the floor.

 

I get no high beams at all. I do get the indicator light on the dash.