It’s always the last thing you’d expect…

Mission made, Brutus roars again.  Damndest thing I’ve ever seen, if I hadn’t seen it I’d be inclined to say “well, maybe in some other universe…”  But I did see it, and reality trumps all opinion.  I’ll tell the tale here, and toss the Gods of Google a couple of bottles of Gatorade (contrary to the rumors the volcano gods of technology don’t really give a hoot about anyone’s sexual history, what they’re interested in is potassium based electrolytes, they actually like the sports drink better than a virgin daughter… no annoying calcium to dispose of) to pass the story on to those who might need and/or deserve to know. 

The culprit?  Sand.  Silicate heavy blow sand to be specific.  Where?  That’s the odd and interesting part. If you’re here trying to fix your truck skip to the bottom of this post for the answer.

After winning the battle of the bitch bolt I set about climbing the system to identify and repair whatever might have been damaged, fixing the cable hadn’t fixed the problem.  Volt-ohmeter in hand into the wires I went.  Of course a VOM is meaningless without a decent set of wiring diagrams.  A week in it was getting obvious accurate documentation is not so easily come by.  But then, lo, manna from heaven!  Knowing of my situation  a coffee shop buddy of mine (Thanks Clay!  Your coffee is on me for A while…) turned me on to a gift card subscription to the Snap-On tools data base where the pro mechanics go for such diagrams.  Pretty much everything said Courtesy of Ford Motor Company… yes!  the gospel according to Ford. 

The longer I studied the diagrams the less sense anything made.  None of the readings I was getting really made sense to the diagrams even though these diagrams matched the truck at the +99% line.  Most critically everything on the ignition is unplugged, all the VOM can see is wires and yet there’s still a 1.5 ohm path to ground somewhere on the most critical circuit of all?  That’s damn near nine amps at system voltage, plenty to siphon down voltages below critical  limits of the ignition components and yet just enough resistance to not blow the fuse.  Well, at least the intact fuses are explained, but damn it, where’s the freaking leak? 

I started taking things apart looking for some glowing green acorn size ball of corrosion or some errant screw poking a wiring bundle just wrong, using the trouble shooting techniques learned in the chemical plant days, isolating things, rechecking readings after each step.     Any change?  Nope, no change.  That’s not it.  Several theories exploded in fireballs of various size.  Two days later I’d looked at pretty much the entire system.

Then… a hope.  The diagrams specified a 500 ohm resistor across the circuit feeding the charge indicator light, other than the main hot lead from the ignition switch the only part of the ignition circuit to cross the firewall, a prime suspect from the beginning.  Wait a minute… if someone repaired that circuit at some point and misread their resistors, say installed a five ohm resistor instead?  Recheck basic DC theory… parallel resistances, unknown light bulb and 5ohm resistor… yup, close, that gets close, and the wire that goes there comes off right after the ignition switch, way upstream of everything else and then ends up at the voltage regulator… regulator was as old as everything else but still doing it’s thing, maybe just a bit slower than in its’ youth, but in it’s old age degraded to the point the process of switching off the alternator also knocked down the ignition about every other cycle? 

That theory fit the behavior of the beast in the dying days.  Worth a look.  I’d already changed out the voltage regulator earlier (one of those $20 things just because it had to have been taking a hammering to the bad ground cable), so out came the dash cluster, out came the little light bulb.  Damn.  Nope.  Printed beside the resistor on the circuit board the caption “510 ohms.”  VOM says 508ohms.  Close enough for me, particularly with the resistor still soldered in circuit.  Drat and damn.  Where is it?  I’ve looked everywhere.  Then the scary realization, no, there’s one more thing you really haven’t looked at: the main bulkhead connector where all the wires go through the firewall.  If it’s broken internally then who knows what’s contacting what.  Oh, shit.  I Do Not want to have to change out that beast.

I’d had that connector unplugged several times, thought I’d looked it over pretty closely.  The pins inside were clean, no sign of corrosion, no telltale tracks of carbon arcing,  the outer shell normal Ford gray plastic.  Wrong.  It’s not gray plastic, it’s bright white.  This fact revealed itself to me the fourth time I unplugged the beast.  A dime size fleck of gray fell off, so thick it looked like old paint pealing away, revealing the true color of the plastic beneath.

Long and short of the story?  After twenty years of service, a great deal of which was spent working for a fellow who ran country roads habitually, drug back hoes around, no doubt spent a great deal of time around construction sites, the outside of the shell was one monolithic coating of silicate crystals so uniform as to fake it for gray plastic!  High resistance conductive silicate crystal grown from cement and blow sand dust that with each exposure to any water at all (just normal Oklahoma mug humidity at the end of the day as things cooled an ideal source) dried into a truck killing semi-conductor!  

He’d start, things would get warmed up, the copper pins in the unsealed holes in the back of that connector would swell some minute amount with the heat and make contact with some portion of the layer producing truly random cross circuiting.  The whole affair temperature and humidity sensitive as all get out.  The last thing in the world I’d have ever expected.  But the facts as reality presents.  I washed the bjezus out of the connector with distilled water followed by electronic cleaner and Lo!  Every reading suddenly totally believable, and no more mystery 1.5ohms to ground.  The fix found.

Moral of the whole affair?  Distilled water baby, not fancy-shmancy bottled drinking water for the yuppie children but true distilled water, flat, non conducting, mineral absorbing distilled water.  Should I ever take on another old beast of the same sort that’s gonna be an early thing:  unplug those damn connectors and soak them for an hour or two in distilled water giving them a good shake every fifteen minutes or so, and then blow another gallon through them with a siphon air chuck.  Short term exposure to distilled water is harmless to plastic and copper.  Then get the electronic cleaner to take off anything oily left behind.  Just to be on the safe side, you know?  Fool me once shame on you, but fool me twice?  Nah, ain’t gonna happen.

Next.  Right.  Next.  Brakes, backer plates out.  I want whoa to match the go… and yea, Brutus has his go back, all five hundred ponies worth.  *grin*