I've got a weird issue, hoping someone has experienced this before.
I swapped my radio out, all worked well. The issue i'm describing is likely a coincidence that coincided with the radio swap, but figured i'd include it.

After the radio swap, or rather during, the truck started acting like the batteries were dead.

• insert key, no ding.
• Move key to start position ( just before run ), lights on dash would light up, but be very dim, and if you tried to start, the truck would pretty much do nothing, no click, no attempt to start nothing.
• Every time I'd move the key, R2 under the dash (Relay 2) would click and the door lights would flicker, non stop, the only way to stop it was to shut the door.

My wife got tired of me talking about it so demanded I show her. So we went outside to show her, and it was fully corrected. No issue with starting, no issue with the clicking, just stopped, after two days of this. However, when the truck did come back on, a few things were wrong.

• I have no headlights, and no brights.
• I have blinkers, hazards, tail lights, brake lights, and license plate lights.
• I have interior lights
• I have parking lights (Orange front lights)
• I have dash lights (I do not have the light for headlights, bright or otherwise).
• When I move my 4x4 switch, nothing appears on the dash, but I hear a clicking under the truck, it never engages, and never updates the light on the dash.

I have checked the following voltages and confirmed not an issue.

1. Starter solenoid is fine, and tight. When starting, it's getting over 12V. When NOT starting, I do not know, it started working before I tested that.
2. Batteries are both resting at 12.5V
3. When running, both batteries are over 13V
4. Headlight switch will chime and ding as expected. It will adjust dimming, it will turn on and off inside lights, and it will control parking lights. Voltage to all lights are correct (except headlight).
5. I replaced the headlight switch, still no headlights.
6. I replaced the steering wheel stalk switch, still no headlights.

I'm at a loss as to what else it could be? I have no water intrusion on the windshield and the GEM looks to be fine. I have no other issues other than this 4wd issue and the headlights. All fuses are good, I replaced the ones that control these items for good measure.
What else can I check and /or am missing?

As of right now, truck starts, runs, no service engine light. I haven't had a repeat of this weird relay clicking, truck acting like it had bad batteries. It stars every time now, but i need headlights, and I don't know what to do short of just bypassing the switch all together.

 

Model year, engine, and transmission?

Multimeter and comfortable using it?

 

I have multi meter, can use it.

2001, limited 4x4 7.3

 

Okay, let's focus first on the headlights since they're still inop.

1. Check fuse F30 under the hood.

2. Does the Flash-to-Pass work? Pull MFS lever towards you, both high beams, along with the cluster indicator *should* come on with the headlight switch off. If the healight switch is in HEAD, bot low and high beams on both sides should come on.

3. If #1 is okay but #2 failed in all regards, use your meter and go check both sides of F30. Should be ALWAYS HOT on both sides.

Update and we'll see where that takes us.

 

F30 is always hot.
The stalk being pulled results in no flash to pass. Nothing on the dashboard lights up when you pull the stalk and headlights do not flash or turn on in any way.

 

I just realized I misread the schematic regarding the fuse for the headlights.

The correct fuse is fuse F10, a 30A fuse. Misread the fuse value to be the fuse number. Sorry for the confusion. Please recheck the above but looking at F10.

 

I'm using : https://www.startmycar.com/ford/excu...o/fusebox/2001

10 under the hood is a 50a Fuse. Can you review the link I gave and confirm you're in the right place?

 

I'm in the factory service manual for what you identified as your vehicle, not some random internet site.

Now, if YOUR underhood fusebox is different, post a photo of what you have and I'll see if I can sort it out.

 

Nope,

I see the issue. F10 is just 39 on the count spacing, we're looking at the same schematic, i'm just not using the F numbers.
That said, this fuse should have constant power, even when headlights are off? Is that right?

 

Yeah, it looks like they used some goofy numbering scheme in their chart instead of the Ford numbering.

Yes, F10 should be ALWAYS HOT per the note on the schematic.

 

Okay, just went out, i'm getting 12.73 volts on both sides of the fuse when I ground it.

 

"ground it"? Have no idea what that might mean in this context. You should be measuring between the two fuse test points (red lead) and the black meter lead should be on a known ground such as the battery negative post or the engine block etc.

If you indeed are measuring correctly and have battery voltage on both fuse terminals, it's time to check for that power feed at the MFS and at the headlight switch designated by red arrows. If they both fail (and since you already said you replaced both switches), the odds are that there is an open circuit in the area represented by the rectangle. How that relates to the physical wiring under your hood is a different issue (grin). Might be an open circuit in the fusebox, the wiring, or at the splice.

 

I put the red lead to the fuse, and the black lead to the negative terminal on the battery. Sorry for the confusion.

As for the light switch, I've tried this a few times. I'm having a hard time figuring out which wire is what on the MFS. I was going to jump the wires at one point to bypass the switch and prove it was the issue.
Something of note. Whoever owned it before me was too cheap to buy the fog light replacement switch, so they went with the more readily available non fog light switch ( the one that can't pull out ). I've got one on order, but the lights were working prior to the radio upgrade so i doubt that's the cause, but figured i'd mention it. I replaced it with the same switch thinking that was the proper switch, when I realized " Hey, I have fog lights but can't turn them on ", I used some basic logic to realize they just had the wrong switch in the truck. IT plugs in, and worked, it's just missing fog.

 

That would be the dark blue (DB) with the orange (OG) stripe - DB/OG

 

Let's treat me like an idiot if you don't mind.

If the MFS is unplugged, which it currently is. Should the dark blue with the orange stripe have 12v to it? Is that what i'm checking for?