Nothing but replacement and alignment procedures in my book. It appears Ford diagnoses it by watching the data from the digital transmission range sensor (neutral switch).

 

Not as far as I know. When I went through the water a couple years ago it was to the bottoms of the doors but I never stopped in it. If the vsm got wet it was because it splashed up and came through a hole some place.

 

And Ok. I kinda thought as much. I'm wondering if the problem or at least some of my problems lie in the vsm being faulty.

The 4lo issue may be a broken wire somewhere along the lines that I haven't yet found yet

 

Went out today and cleaned up some wiring from previous owners and had a decent look under the dash. Can't find Any wiring that is obviously buggered.

I did notice that with the inop running lights and dash lights that when I lock my truck the tail lights no longer illuminate when I push the button. I also pulled the vsm out and had a good look at it. It doesn't appear to have any water damage or anything. It visually looks fine.

Whatever this electrical gremlin is, it sure is a doozy.

I almost feel like I just need another truck just like mine to swap modules with to see if it corrects anything. I don't want to shell out the cash for new ones if I don't need new ones.

 

Wish I knew what actually controls each individual thing. All my problems started and have been progressively piling up ever since I went through some mud 2 years ago and when it rains sometimes my truck does funny stuff like the blower motor will stop working and then start working again.

I've always wondered if it was all, or mostly all, connected.

 

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rlebar,

I think you have two separate problems. One is the original 4Lo fault and another is electrically connected to 4Lo giving you a second faulty state.

The worst problem to find is probably in your steering column. All your accessories and 4Lo are wired to the ignition switch.

If you have tilt wheel, the tilt sometimes stretches connectors and wiring. If such a problem is intermittent, it often works in non-tilt but pulls a connection loose in tilt for a failure. This happened to my Excursion.

Another steering column bug is the electrical part of the ignition switch and associated linkage. The key lock assembly has to physically connect to a sliding electrical switch with a crank mechanism. The joint must be adjustable so that the electrical position (acc, ign on, start) setting will correspond with the correct key notch. Since it must be adjustable, the slide-switch locking screws can come loose causing the truck to start, or accessories to come on, in odd key positions, or more likely, partial in-between positions. The key cyl/ switch linkage can also become loose rather than the adjustment clamping.

The clue is that weird intermittent stuff happens with your acc. This is likely how they are all connected as you suspect. This happened to me on a K-10 Chevy once. Hope this helps and good luck.

Wes
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That's worth looking into. Thanks I will look into it as well.

 

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rlebar,

You are welcome, hope it solves the riddle.

Upon further investigation, it appears that the electrical part of the switch may be rotary on a Ford. I can't tell from Chilton pictures. The same rules should apply, that the switch contacts correspond with the key notch and can be set to do so. It is still the most likely cause of accessories operating, or failing to operate, when the key position says otherwise.

Before removing the steering wheel, if you do, be sure to disconnect both the negative battery terminals and allow a couple of minutes for the system to bleed 12v+ off. They retain power for a bit after a collision may cut main power. A too-close airbag can break a mans neck.

The steering wheel can be removed without a puller, sometimes by merely pull-torquing it side-to-side, or tapping the semi-loosened nut with a plastic or wood-protected hammer while pulling slack up. EX: On stubborn wheels I hold the steering wheel up with my knees and tap the steering shaft. Good luck, again.

Wes
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Well good news for me with the running lights. My first inspection of all the fuses came up with nothing but today I looked very carefully at every fuse. Turns out fuse 17 was blown and now my running lights work again. Why the fuse went is still a mystery but it's working for now.

As for all my other electrical problems. That's anyone's guess still

 

The fuse keeps blowing.

It instantly blows if I turn my high beans on, otherwise it blows within about 5 minutes of having my running lights on.

This is too big an issue to let be.

I really need wiring diagrams and accurate inventory of what each fuse is for in the central junction box.

I have some diagrams and a sheet that is supposed to be for my truck telling me what each fuse/relay is for, but it's not accurate.

I also found a bad relay in there, but after getting one that works, nothing has changed so I don't even know what the relay is for.

So I need a wiring diagram for the light system for my truck. And a sheet saying what the relays and fuses are for in the central junction box. I have a bad wire somewhere and I need to find out where to looj

Truck is a 2003 f250 xlt scsb 7.3l powerstroke.

 

Only thing for fuse 17 that I can find is page 1 of the power distribution circuit that has the Tan/wht wire go to the main light switch and split at a plug and also goes to what I assume is pin 8 to the vsm.

Can this be confirmed? In any case I will be taking a close look at that wire hopefully tomorrow. I have to do my rear u joints tomorrow anyway. What I don't understand is why that fuse gets blown when I turn my highbeams on.

Wish I had a diagram of the main light switch showing wire colors and where each went to specifically.

 

PM awaits.

 

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The direct battery headlight circuit appears to power the VSM which powers doorlocks. Do the doorlocks work? Is a lock motor, or wire shorted?

Wes
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No the door locks work fine. I will throw another fuse in it later and see if the door locks or Windows trip the fuse.

The door locks and windows have never been a problem. Again I'll double check them later as well

 

ok. Door locks check out fine. They've never been an issue infact. I mentioned it in my first post because sometimes the auto lock and unlock button wouldn't work on my key thingy. Turns out it was just my fault. I disconnected the antenae.

From what I could see of the tan/white wire, it wasn't disrupted or damaged anywhere I could see/reach. There is a section of that harness that goes pretty deep behind the dash that I can't get at though.