I'm not great at electrical troubleshooting, but I have a thought/question.

Remember the first part of what I said before you react to my question below.

Any chance it could be the IPR going out? I experienced the "no start when hot" condition when my last one failed.

I guess it all depends on whether or not the no start condition is because the engine will not crank (turn over), or whether it cranks but will not start. If it is truly no crank (no engine turnover), then just ignore my question.

 

It's a no crank.

 

You’re talking about the electrical switch here right?
Dude, I’d start right there.

 

Oh she was shiny and clean when I got done with her. All the same, I got my parts in today so I plan to swap out the switch at least, before heading out tomorrow. If it doesn't fix it then one step closer I suppose.

 

Did you ever take photos or post a write up on removing, disassembling, cleaning, reassembling, and reinstalling your ignition switch (white box component)?

That might make a nice addition to the Tech Folder if you did (or if anyone knows of someone else who did). I looked for, but did not find an existing write up on ignition switch cleaning... only replacing.

 

I can try going through my old photos to see if I took pics this evening. If not I can take it apart again now that I've swapped it out. It might cause a little permanent liver damage, but anything for the cause right.

 

@Y2KW57 I decided it would probably be easier to just take apart the switch than go on an archeology expedition looking for pics I might have taken. So here she is, our ignition switch. The electronics equivalent of a spool valve.


One step I wasn't able to show is removing the 2 rivets, one at each end. Just a small drill bit to remove the head and they come out.

A small screwdriver or pick to pry the tabs out will split the case.



Here's where the magic happens. Those little copper "skates" are spring loaded to keep pressure on the contacts as the "float" slides between the different key positions.

Notice the little ball bearing in tray.

Those 2 springs in the underside of the "float" are the return between run and start.

Once everything is properly cleaned and fresh grease applied it all pops back together easy enough. I just found some properly sized screws to replace the rivets, but if you're wanting to be all fancy I'm sure new ones could be reinstalled.

 

This is beautiful work, @udsuth78 .

If you don't mind, I'm going to lift the posts related to your ignition switch exploratory surgery over to a new thread dedicated to ignition switch diagnosis, as FTE doesn't have a dedicated thread (in any subforum) on this ignition switch, and the write up on the Mustang forum has published errors in the pin continuity combinations that I suspect cause some folks to needlessly replace fully functional ignition switches.

To carry on with the present thread on your current problem, please let us know if the new ignition switch changed anything under similar circumstances (hot crank).

It will be especially important for our community to know this.

My suspicion is that the issue is not in the switch... UNLESS, the removal of the two rivets that you drilled out, if not replaced with hardware of equivalent clamping force, caused an intermittent gap between the copper bumps and slides, now held together only by the plastic pawls on the sides of the switch, which are not as tight as the rivets that were removed.

 

It’s been a whole day and a half…. Too soon for a verdict?
Curious minds are anxious to know the outcome!

 

Use it however you please. Once it's on the internet it's fair game in my opinion.

You would be correct. I really wasn't expecting it to be that easy either, but it was an inexpensive shot in the dark compared to some of my other rounds of part darts. I'll wrap up the old one and stash it for a back up.

Now to bring everyone up to date on what has developed into a plain ol' no crank. The no crank began before swapping the switch or lock assembly so I know neither of them are a cause, at least not directly as yet. So after swapping both parts I checked continuity from the red/light blue to a wire I've strung to the trigger terminal on the fender relay(that went in after the no crank became a permanent issue) and got a reading of 0 ohms. Turn the key to start and click nothing. Switch my meter to DC V and key in run reading 5.5v in start 12.5v round abouts, but no love. Hit my jumper to a 12v source and crank and fire. Check everything again later in the day and get OL for continuity and seeing the 5.5v in run. I'm also showing 0 resistance to ground at my jumper. Electrical isn't my strongest suit but I'm betting that isn't supposed to be like that. I'm getting close to tapping the wire after the fuse box and run a new wire direct to the relay. I'd rather not bypass the range sensor but I'm not going to fight it either.

 

Did your truck ever have an alarm system installed?

 

Not that I'm aware of but honestly idk. Any signs I can look for to rule it out? I've never messed with car alarms. My town is bustling with 25-30k people, the most I have to worry about in that department are kids riffling for money and cigarettes. Then there's meth heads taking batteries and such. Unpleasant sure, but not worth the hassle of having an alarm go off in the middle of the night because of a storm. Hell most of the time the keys are in the ignition 24/7.

 

Some alarm systems, particularly the type from 20 years ago that were voltage based, rather than data signal based, called for cutting and splicing the start circuit, the ignition circuit, or both.

These serially spliced (not wyed or paralleled, and this distinction is important) circuits are then fed to the alarm control unit, which has a couple of high power relays inside of it through which these circuits are routed and then returned back to where they were originally destined by the vehicle manufacturer, prior to being cut into by the alarm installer.

The alarm's circuit board controls the trigger signals of the high power relays inside the alarm's control box.

If the required conditions are met (unlock button is pressed on keyfob, with no indications of forced entry, as an example), the relays are closed and start and ignition power is directed to where it should be to start the vehicle.

If the required conditions are not met (glass breakage sensor triggered, as an example) the relays inside the alarm brain remain open. Start no workie.

Now, if the alarm was abandoned in place, the key fobs long lost, and the alarm never used, or never even known about by subsequent owners of the vehicle... and the alarm control box was not removed, it is possible that the ignition and start circuits are still being routed through the high power circuit board mounted relays inside of the alarm control box.

If those relays fail open, due to the normal degradation of electronic components that are pummeled with a surge of current at every start cycle, then no workie.

I experienced something similar to this within the last few days, when I recently traded in my FORD for a SIDD. I'm in the process of unraveling all the alarm system splices right now.

Your post history suggests that you have been struggling with this no start issue for quite some time, with each go around getting worse and worse, and now you are staring down total failure.

The gradual break down you report is similar to the gradual breakdown in some electrical components, and since you have changed many of the Ford electrical components, it made me wonder if there were some hidden aftermarket components buried deep beneath the dash that were left over from previous owner "upgrades".

 

So today I remembered I have one of those Harbor Freight cable tracker things and decide to give it a try on my ignition. So I actually read the "destruction's", hooked it up and track the signal to the range sensor but not back out. After 45 minutes and whole lot of cursing I got the connector off to see it looks fine. Side note whomever decided it was a good idea to put something that critical in such an exposed location with a connector so easily packed with mud and crud needs kicked in the Dick's Sporting Goods repeatedly. Anyway I did go ahead and adjust that bracket from the cable to the sensor while I was down there and pissed off. Buttoned her up and checked continuity 0 ohms, voltage 5.5 in run 12.5 in start but no crank. Go for a drive, stop recheck everything, no change. Put in neutral and check, no change. Back to park and it cranks. WTF? So far it's started 2 more times and no misbehavior, so idk.

 

Bad connector at the Range Selector Switch connector and your meddling with it reestablished contact maybe? Hit it with some contact cleaner like DeOxit.