Dryer Explosion

[ridindirrty]

Pretty much what i figured. The one corner (passenger front) just seems to stay at more or less the same height no matter what. I haven't ruled out something binding in the front end either. What would the system do if there was nosignal at all coming from a height sensor?
My new (rebuilt) compressor doesen't have a schraeder valve, I take it there were some design changes made over the years?

 

[Elessee]

My new (rebuilt) compressor doesen't have a schraeder valve, I take it there were some design changes made over the years?"

last year or so when i was talking to American (?) about my squirting Tire Fixit into a leaking air spring (it worked, btw) we also spoke about compressors. He said he won't supply the schrader valve anymore because people misused them somehow, toasted the compressor and then demanded a refund..

I forget what exactly that misuse was..

 

[OldSchool1]

Where'd It Go?

Pretty much what i figured. The one corner (passenger front) just seems to stay at more or less the same height no matter what. I haven't ruled out something binding in the front end either. What would the system do if there was nosignal at all coming from a height sensor?

No signal would be an open circut. An open circut means that the sensor has met ride height (extended sends a HIGH signal and compressed sends a LOW signal). Meeting ride height takes the air spring's solenoid out of the suspension equation but it does NOT stop the compressor from reacting to the other two sensors. If this happened AND the air spring went down with a closed solenoid, then we're 99% sure that the air spring has a leak.

My new (rebuilt) compressor doesen't have a schraeder valve, I take it there were some design changes made over the years?

It may be after market. I'm away from my 90 and 91 so I can't give you a definate at this time. I know that my 84s through 89s have them.

 

[OldSchool1]

Spring Misuse In The Fall

... I forget what exactly that misuse was..

KaBoom

The schrader was designed to be used only in emergency. Specifically, when the mechanic/owner/guy-down-the-street forgot to turn off the suspension switch before jacking/lifting the vehicle. Once the vehicle is lowered, depending on the height of the lift/jack, the car could come to rest on the lifting device. If for any reason, the suspension system did NOT sense a low condition and RAISE the vehicle off the lift, we were suppossed to turn the key switch to run and manually fill the air springs JUST UNTIL the vehicle was no longer supported by the lift.

Aftermarketers may have removed them to save fourteen cents per unit produced.

 

[ridindirrty]

Never a break

Thank you by the way for the post on removing the overhead console Got 'er done and the check suspension bulb has been replaced. Also pulled and moved the spare and located the pigtail so I can do the self-test. I take it it's that single yellowy-orange wire with the open bullet connector?

It may be after market. I'm away from my 90 and 91 so I can't give you a definate at this time. I know that my 84s through 89s have them.

I actually got my compressor from American Air and it's my understanding they are rebuilt Ford units.

And the saga continues...driving slowly over some uneven pavement yesterday (my driveway) I hear an unpleasant clunking coming from the rear of the car. Thought it might be something loose in the trunk as i had just removed the spare and the jack from it's normal resting place. But alas, no, nothing quite so simple. Took a look under the car only to see a broken REAR sway-bar link now. F**K ME!
Might this be a result of driving the car while the rear end was overinflated (ie -ZERO rear spring compliance)?
One more thought...If my FRONT swaybar links were not properly matched, could this make it difficult for the front suspension to level out properly? I'm thinking it might.

 

[OldSchool1]

Dude.

You ~really~ should start a separate thread for each issue.

Old Dudes like myself can become confused easily.

Thank you by the way for the post on removing the overhead console Got 'er done and the check suspension bulb has been replaced.

You're welcome.
Thank ~you~ for keeping another Mark VII out of the crusher.

Also pulled and moved the spare and located the pigtail so I can do the self-test. I take it it's that single yellowy-orange wire with the open bullet connector?

On a stock vehicle, yes, but double check that it's not plugged into a Flux Capacitor first.

... Might this be a result of driving the car while the rear end was overinflated (ie -ZERO rear spring compliance)?

Possibly.

One more thought...If my FRONT swaybar links were not properly matched, could this make it difficult for the front suspension to level out properly? I'm thinking it might.

We charge extra for one more thoughts.
Our Anti-Sway Bars are designed to reduce front wheel drifting from left to right and are connected to our vertically installed End Links. Neither should hamper ride height unless the vehicle was used to shoot an episode of Dukes Of Hazard and jumped the bridge once or twice.

 

[ridindirrty]

You ~really~ should start a separate thread for each issue.

I hear ya - in my world though...these issues are all related. I see what you're saying though.

Thank ~you~ for keeping another Mark VII out of the crusher.

I'm trying, sometimes i have some pretty evil thoughts...but i'm trying.

2 new rear swaybar links installed.

 

[ridindirrty]

Do the 10 point suspension test... ground the pigtail on the on-off switch in the trunk. Get in the front seat.. all doors closed.. Turn the key to RUN..

Well, I ran the test, what a handy feature. I think I actually like the fact that you DON'T need any special scanner to do said test.

Got to test #2 "RAISE RF" ... low and behold ... it couldn't do it. eventually it just gives up and the CHECK SUSPENSION light just glows steady.
As i said before, this corner just sits consistently low ALL the time now, it doesen't lose air as it sits though so it doesen't appear to be leaking. If I turn the suspension switch OFF and turn the key to RUN, the nose of the car drops right down so the solenoid would appear to be working.

I'm still confused but at least I have confirmation of that corner being the issue. Hmmm...now what ?

 

[Elessee]

--
[..and the CHECK SUSPENSION light just glows steady...]
----

Can you advance to the next test, and the next? (Open and close the driver door a couple times.)

If yes, advance to test #7. The lamp will blink 7 times, pause, and repeat.

This test opens and closes the Right Front solenoid, once per second [pump is off]. You can hear the solenoid clicking if it's quiet enough [or put a finger on it]. That corner should drop if there's some air in the spring..

Test #7 will confirm that the RF solenoid is actually fully functional. Full functionality means it's electrically operating and it's passing air when it opens.

([edit] On test 7, the main vent solenoid in the pump body is also opening and closing.. that is, it should be. )
----
Advance through all the tests if you can. Keep notes of what happened.
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Take it slow to avoid jumping to false conclusions... combining all the tests with some logic might isolate a bad component.

I'd recommend drawing a diagram on paper with suspension components, and check off the ones that positively are working properly..

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a couple of things i noticed..
A completely empty spring might require a full minute or more before it even begins to raise it's corner of the car.
Pumping up just one corner, right or left, can raise the other corner substantially. And draining one corner can lower both corners..

 

[ridindirrty]

Suspension Self-Test

Can you advance to the next test, and the next? (Open and close the driver door a couple times.)

If yes, advance to test #7.

It just seems to repeat test #2 repeatedly, I'm assuming because it can't complete it?
I'll try again anyway and see if i can make it advance. I had the very same thought last night as I was doing it. Even though it got hung up on test #2 I still wanted to go through the other tests to check everything else.
Thanks for the input as always.

 

[Elessee]

"...It just seems to repeat test #2 repeatedly, I'm assuming because it can't complete it?"

maybe.. to tell the truth I don't know what sort of fault would prevent the diagnostics from advancing to the next test.

It seems pretty odd if system-diagnostics is designed so that one failed test would prevent any of the rest of the tests from being executed. Some tests are completely different from others.. makes no sense to stop everything..

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"...eventually it just gives up and the CHECK SUSPENSION light just glows steady...."

See if you can move quickly from test #1 to #2 and to #3... don't wait for #2 to fail.

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If it can't get past #2, I'm thinking it might be a wiring fault.. Something to do with that Right corner.

When the controller tries to operate that corner, some fault (like a grounded wire or a shorted wire) hangs it up and the system crashes.

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I might try disconnecting the RF solenoid connection at the solenoid. See if Test #3 is then available. IF so, the solenoid's internals or the connector or the wiring might be the problem.

I don't recall where the other end of that RF solenoid wiring is connected, but if i knew I'd try disconnecting it at that source.

And/or, disconnect the RF height sensor wire...
---------

One other thing.. this Suspension system will act weird if battery voltage drops below something like 11.5 volts, if memory serves. It's a good idea to leave a battery charger attached all the time..

 

[ridindirrty]

Self-Test Completed

If it can't get past #2, I'm thinking it might be a wiring fault.. Something to do with that right corner

I went back and tried again and I was indeed able to proceed to the subsequent tests. Guess what happened when I got to test #7?
Uh huh...sweet F.A. The solenoid is doing nothing. I pulled the connector off and cleaned everything out with electronics cleaner, put it all back together...nothing. Corner did not level.

So, either: a) the solenoid is toast b) the connection is bad c) there's a wire grounded out in the harness.
I can't see the computer not firing just the one solenoid when everything else is working fine.

How can i check for continuity at the connector without the system being live? Will a 12v test light do it? Sorry, i'm not great with the electrical stuff but i can follow intructions reasonably well.

I'm afraid to change out the solenoid and empty the bag because if that's not the problem then i cant get air back into the bag . I'll need to verify the electrical circuit first somehow.

I'm getting close...very close

 

[Elessee]

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"......I can't see the computer not firing just the one solenoid when everything else is working fine....."

Me either..
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First check the solenoid for continuity.. (you can leave it installed in the spring for this test)

Set a multimeter to Ohms. Apply the two red/black probes to it's contacts.

The inner coil's "resistance" should read something between the tens and hundreds of ohms. (i'm just estimating).
If the internal coil is toast the coil wire is broken and it'll be an open circuit, and meter reads infinity.
(It's got a coil of very thin wire wrapped around an iron core.. it's a simple electromagnet)

Or remove the bad solenoid and move it to a working corner.. like the left front. Confirm it still doesn't work.
------------

To test the cable.. a 12V test lamp should do it .. but meters are cheap.. the grocery store might have one in the hardware isle.. near the oil.

To get current running through the wires, you could run a diagnostic test... like Test #7 with the meter set to volts, [OR with the lamp hooked into the connector] and the probes on the wire connector contacts.

It should flash 12 volts and off, 12 volts and off. At least the meter will jump once per second. It'd be better to use an analog meter rather than a digital.. With an analog meter you can see the needle move. With digital the electronics may not recover fast enough to read once per second.

---------------

You can also substitute a solenoid from a working wheel to check the Right Front cable/connection..

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i'm gonna guess... and it's purely a guess.. that neither of the two solenoid wires are supposed to be grounded to the frame. The negative wire might be directly connected to battery-ground and the frame-body, but i doubt it.

But if it's not, you can use the ohms setting on the meter to confirm that neither wire is wrongly grounded to the frame. Attach one probe to a wire and one to the frame. There should be an "open circuit", and the meter reads infinity.

---------------
Whats the big deal about an empty spring.. you have to drive this thing everyday?

 

[ridindirrty]

Yep, it's my only car

Whats the big deal about an empty spring.. you have to drive this thing everyday?

You got it. This car is actually my beater but my other car (85 Mustang) is unavailable to me at the moment.

I have procured a bunch of used solenoids and this is the plan:
Gonna jack up the car to get at the solenoid connector, unplug said connector and plug in one of my new(used) solenoids leaving the original one in place in the airbag on the car.
Put the car back on the ground with the new(used) solenoid plugged into and hanging from the connector pigtail.
Run the self test and quickly advance to test #7 and see if that puppy fires.
If so...i know what my problem is.
If not... i know it's a problem with the harness OR computer(which I doubt).

 

[Elessee]

cool.. if any one of the used solenoids works, it means the connector/cable is working too.. While test #7 is running, you might unplug one and plug in another solenoid. Mark the ones that work. If none work.. well.. then nothing at all was proven by the test.

On old solenoids, the two small O-rings near the base really should be replaced with new ones.. also pull the internal airline clip thing out and replace the tiny one in there. The Ford rebuild kit was $20 and on the shelf when i needed one. It had a new clip and the several o-rings in the package.. enough for one solenoid.

To take the airline clip out, get a piece of junk airline about a foot long. Push the end into the solenoid. Wrap the line around your fist and pull hard. The clip will pop out. There's a chance of damaging the airline so using some spare piece is recommended.

The time to replace o-rings is before everything gets put back together (if you find a solenoid that works). It's nice when the car stays at normal height although parked for months on end..

The neoprene O-rings seem to take a set with age.. the surface gets microscopic dents and flat areas and O-rings are bound to leak if not perfectly round. I actually put mine under a low power microscope to understand why an O-ring that appeared perfectly OK allowed a slow leak..

 

[ridindirrty]

Now What?

First check the solenoid for continuity..

Did that AND checked all the used ones that I picked up. The reistance appears to be at or about a little less than 100 ohms across the board.

To test the cable.. a 12V test lamp should do it .. but meters are cheap.. the grocery store might have one in the hardware isle..

My findings. I tested for voltage across the 2 terminals on the connector (on the bad corner). There is a continuous 12 volts. This is obviously wrong but what does it mean? This is when the car is just sitting there, key not even in the ignition. Did the same test on the other front connector and as I would expect...no voltage, (unless the solenoid was being energized).

You can also substitute a solenoid from a working wheel to check the Right Front cable/connection..

Did this, ran test #7, nothing happening.

I'm out of ideas.
Could the computer be doing this?

 

[Elessee]

100 ohms seems about right for a solenoid coil.. since they are all the same, it's confirmed they are ok, imo. Apply 12volts to a solenoid. Use the car battery. They should click.

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[EDIT] Future readers diagnosing their suspension might well skip this "Reply" because one of these wires is supposed to be hot.. There may be some useful information as applied to electrical stuff in general, so I'll leave it intact as written. [end edit]
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The 12 volts connector reading means one of the 2 wires is connected to a 12V positive source.. probably an adjacent 12 volt hot wire.
The other of the 2 wires is grounded.

That forms a completed circuit.
Battery positive---unknown hot wire--[short circuit]--one solenoid wire--[voltmeter]---grounded solenoid wire--battery negative (ground)


Lets say two wires are laying close together. One is "hot" and the other is not.
You then tighten a bolt and, being caught between two pieces of metal, those two wires are crushed together, breaking the insulation. The wires make contact. Both wires are now hot and the previously "cold" wire will read 12V.

Or.. Sometimes a hot wire (carries 12 volts) is overloaded.. it copper gets very hot and melts wire insulation before the fuse blows. You replace the fuse. Now, several wires surrounding it might then become "hot" wires due to burnt insulation..

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I'm wondering why the solenoids wouldn't 'click' once immediately when attached to that "hot" connector.. Do they? You don't need to enter Test #7 to check it if the connector is always "hot". Just stick one on the hot connector.
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While it's theoretically possible the controller is doing it, it's unlikely that it's doing it to one solenoid alone. And if the controller were sending a constant 12 volts through the wire, your battery should discharge very quickly while parked.

It's more likely that you've got a short circuit where a hot wire is mistakenly contacting a solenoid wire..

Meanwhile, that connector hot wire is sending a constant 12 volts backwards up to the controller and screwing with it's brains.. And considering the potential consequences of that, it's possible that the controller has been fried or somehow corrupted..
But there are cheap, simple ways of protecting the controller from such abuse.. so it's questionable.
-------

[edit] .. so far i haven't opened a manual, looked at an electrical diagram, or got off my butt to open the hood.. I will if you ask. I hope you do a little bit of visual inspection before asking me for wire color codes and where various wires are routed..

 

[Elessee]

ok.. hold the horses..

I looked at the wiring diagram. One of the wires on the connector is supposed to be always "hot". It trails to a "fusible link", and then directly to Battery positive.

The Black/Yellow stripe wire should be the hot one. It's always hot.
-----------

The Orange / Red stripe should go to the controller and should not carry 12V. And, it should not be grounded. The Orange/Red should be an open circuit until the controller closes the circuit. Closing the circuit activates the solenoid.

Set the meter to Ohms. Put a probe on the Orange wire connector contact. Put the other probe on the frame of the car. Meter should read infinity or very high ohms.. If it reads few or zero ohms, that wire is mistakenly grounded.
--------

You would not see 12 Volts between these two connector wires on a properly functioning corner of the car. The reason is because the Orange wire is (normally) not connected to anything.
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lemme know what's up and we'll move on from there..

 

[ridindirrty]

Great Info

Set the meter to Ohms. Put a probe on the Orange wire connector contact. Put the other probe on the frame of the car. Meter should read infinity or very high ohms

Great info, will do, won't be until tomorrow evening though.

You would not see 12 Volts between these two connector wires on a properly functioning corner of the car. The reason is because the Orange wire is (normally) not connected to anything.

Do you think the problem could be in the actual connector? I've mentioned before that this WHOLE odyssey began with some front end work being done on my car. This mechanic told me that one of my solenoid connectors DID NOT appear to be fully inserted. He told me he plugged it in fully but there was resistance (ie. it seemed difficult). Could jamming this connector on slightly off kilter have damaged the plug somehow and caused the terminals to bridge ?

Just an idea.

 

[Elessee]

"...Could jamming this connector on slightly off kilter have damaged the plug somehow and caused the terminals to bridge>..."

You have the tool .. the ohm meter.. that can detect if two wires (or two terminals) are connected. As simple as it is, the ohmmeter is very versatile.

--------------------
It's handy to know how the meter detects a connection.

The ohmmeter sends a low-voltage current into whatever you connect it to.. probably about 3 volts. That's one main reason why the meter has batteries.

When one probe sends exactly 3 volts and 3volts are detected the other probe, the meter knows that no voltage was "lost" or used up due to "resistance" (ohms). That circuit is perfectly "closed", and the meter reads Zero ohms. (zero resistance)

But if the 3volts sent out at one terminal comes back as only 2 volts, some voltage was lost. Therefore the meter detected some resistance, and it might calculate something like 3,972 ohms of resistance in the circuit. (a fake number used for example)

If 3 volts are sent, and no volts at all come back, the circuit is an "Open" circuit... meter reads Infinite (or very high) ohms.
--------

The practical point of illustrating that is that you cannot use an ohmmeter on wires or in a circuit that is already carrying voltage or the voltages will get mixed up.. the ohmmeter will be confused.
So, before testing that "hot" connector for an internal fault, disconnect the car's battery.

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With the battery disconnected, that hot solenoid connector wire will not be hot. Both wires can then be tested to see if they are connected together, or connected to something in common, like the car's frame.
Sometimes, a little logic makes life easier..

"If A is connected to C, and B is connected to C, then A is connected to B."

The two wires could be mistakenly connected in many, many ways. You hope they are not connected. You hope that you won't have to search for their connection.

IF a connection is detected, and you have reason to suspect the connector body is likely at fault, you would focus on that first... but if the connector is OK, you'll have to investigate further..

Hopefully your meter will not see any connection between the two wires. That means the connector is ok... At least you'll know it's internal contacts/terminals are electrically isolated.

 

[ridindirrty]

So, before testing that "hot" connector for an internal fault, disconnect the car's battery.
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With the battery disconnected, that hot solenoid connector wire will not be hot. Both wires can then be tested to see if they are connected together, or connected to something in common, like the car's frame.
Sometimes, a little logic makes life easier..

Damn...good idea. Another way to eliminate where the problem isn't

The two wires could be mistakenly connected in many, many ways. You hope they are not connected. You hope that you won't have to search for their connection.

Tell me about it.

IF a connection is detected, and you have reason to suspect the connector body is likely at fault, you would focus on that first... but if the connector is OK, you'll have to investigate further..

I would actually be quite pleased if the connector itself was the issue. Splicing in another one of those would be a heck of a lot easier that tracing that nonsense up through the harness and beyond.
F@#K that S%*T!

 

[Elessee]

One thing to be aware of is sometimes the connections in a complicated circuit is not cut and dried, zero or infinity ohms..

For instance, while the Orange wire's connection to the controller should be wide "open" according to theory, it might also be just slightly closed.. and that might be correct.
There may be degrees of openness when dealing with complicated circuits that include things like a main controller.

A wire or the controller itself could seem "slightly" connected to the frame or to other wires (due to a resistor and/or diodes in the circuit).. and no matter where you look, you see a hint of a common connection..
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Fortunately, you have a blueprint of how the meter should read no matter what R-Front connections you're investigating: The Left Front.

The LF is a guide. You can cross reference the meter's readings on the RF's components with those on the (functioning) LF.
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[EDIT] I may as well add this here..
From what i've read so far, my intuition tells me that the R-F Orange/Red wire has been somehow mistakenly grounded .. somewhere along it's length.. and it happened around the time the front end work was done. It's being grounded would make that connection "hot" all the time.
Additionally, due to erratic controller behavior, I have a suspicion the controller may be damaged. (but first solve the mystery of why that connector is always hot, and cure it.. and then see how the controller reacts.)

I've done plenty of weird things while playing with electronic stuff, like cut suspected connectors open.. and they are surprisingly well constructed and tough to mess up.
While the connector might be hanging out there in mid air, easy to access and easy to replace, don't get your hopes too high..

 

[ridindirrty]

My Findings

Right Front

Battery Connected
Continuity across connector terminals - yes - 12 volts
Continuity Black connector terminal to frame - yes - 12 volts
Continuity Orange/red connector terminal to frame - no

Battery Disconnected
Resistance across connector terminals - 10000 ohms
Resistance Black connector terminal to frame - no reading
Resistance Orange/red connector terminal to frame - no reading

Left Front

Battery Connected
Continuity across connector terminals - no audible beep - but .01 volts
Continuity Black/green connector terminal to frame - no audible beep - but.01 volts
Continuity Green/whatever connector terminal to frame - no reading

Battery Disconnected
Resistance of either connector terminal to frame - no reading
Resistance across connector terminals - 1.6 milli ohms

Another Note
I re-checked the resistance across the solenoid terminals with another multimeter. I didn't trust the one I originally used.
The reading for the RF solenoid is .3 ohms
The reading for EVERY OTHER solenoid I have is 16-17 ohms.

 

[Elessee]

"...Another Note .. I re-checked the resistance across the solenoid terminals with another multimeter. I didn't trust the one I originally used.
The reading for the RF solenoid is .3 ohms
The reading for EVERY OTHER solenoid I have is 16-17 ohms..."

Picture a coil wrapped with 500 turns of wire. The turns are insulated from each other. If the insulation breaks down somewhere in the coil, adjacent turns of wire might touch. A current could then move across that short circuit.

For instance, if turn #1 were short-circuited to turn #250, the current path is shorter.. it's cut in half. (250 is half of 500) The ohms reading through the coil would also be halved. Magnetic power would also be halved and there might not be enough to move the iron core against it's return-spring pressure... and the solenoid might not open.
So, if the reading is accurate, I'd say plan on replacing that solenoid.
----

i want to think about the rest of the results before commenting..
-----
OK..
"..Battery Disconnected -- Resistance Orange/red connector terminal to frame - no reading.."

No reading? The is a continuity test. By "no reading" do you mean Zero ohms or infinite ohms?

If Zero ohms, that O/R wire is well grounded (and you've discovered the trouble).
If infinite ohms, the wire is not grounded when the battery is disconnected (but we aren't necessarily finished yet).

 

[ridindirrty]

Just A Thought

So, if the reading is accurate, I'd say plan on replacing that solenoid.

Yeah, I had pretty much concluded that solenoid is toast.

"..Battery Disconnected -- Resistance Orange/red connector terminal to frame - no reading.."

No reading? The is a continuity test. By "no reading" do you mean Zero ohms or infinite ohms?

Yeah, I mean NO reading. No reaction by the meter whatsoever, so infinity I believe.

Just a thought.
If all wires from the individual components in the system run directly back to the controller (i don't know if they do or not), could I (in theory) cut the wires @ the controller & @ the connector (the black & the orange/red) and patch in a jumper that bypasses the harness completely.
THEN Run the self test with a good solenoid plugged in and see if it does what it's supposed to do?

By the way...thank you for the time and energy you've been spending helping me solve this problem. Too cool man.