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I'm sure I got a short.


If you take a deep breath, stare at the wiring schematics and still don't see what to do, what I have done is go to the junkyard and take pictures of one (like - so 4.0 if you can, same year) and after looking at it for a minute decide if you want to rob that whole connector and 2' of wire, cut it off and go home and start splicing.

My radio the original owner did such a number of a job on the wiring I decided I would just go rob a new connector and 1' pigtail to fix the last 3" that were a spliced mangled mess.... I robbed from an F-150 cause the dash is bigger and there is room down by the driver vent to cut the wires there and get 2' cleanly without having to hold pliers inside dash with 2 fingers. But in that case, I KNEW the F-150 had the same connector identical and my junkyard is cheap $1/ft for pigtails... cost me $2 and $15 in gas. (I went for other things that would have paid for the gas had I got em)
 
Your #538:
Connector plugged in or not. Unplugging it will easier to probe the pin. The negative battery cable must be connected to the battery. Ignition OFF. With an ohm reading you are testing the ground circuit's resistance.

Another test, perhaps even mo better, would be a voltage drop test. Meter set to DC VOLTS. Battery connected, C167 unplugged, ignition ON. Test voltage across the battery positive and negative; that will be your reference voltage. Then on C167 test with meter red lead on the pin 7 Red wire and meter black lead on pin 9 Black/White wire. There will be SOME voltage drop, from the path through the added wiring and ignition switch contacts, but the reading should close; say, roughly, within a volt or two.

Your #539:
There several kinds of cable shielding methods, but what I've seen most in automotive applications a bare ground wire next to the signal wires, with a spiral-wrapped strip of foil covering all of those, and then the harness finished with an insulating tape wrap.

The purpose of the shielding is block any stray voltage, also called "noise" or RFI (Radio Frequency Interference) from being radiated into the signal conductors. Basically, if the signal in the wire gets scrambled, the device using that signal can not operate properly.

The next time you're in the bone yard, check the coaxial cable for the old-school car radios. That nice fully-braided copper shielding is needed because AM signals are very susceptible to RFI.
 
I don't know how much the PickYourPart I go to charges for connectors and wiring.
At this time however I've got like $6 to my name.
The worst part of me only having $6 cuz I got bills right around the corner at least $500 of them.
And no jobs in the foreseeable future.
 
@RobbieD

Another test, perhaps even mo better, would be a voltage drop test. Meter set to DC VOLTS. Battery connected, C167 unplugged, ignition ON. Test voltage across the battery positive and negative; that will be your reference voltage. Then on C167 test with meter red lead on the pin 7 Red wire and meter black lead on pin 9 Black/White wire. There will be SOME voltage drop, from the path through the added wiring and ignition switch contacts, but the reading should close; say, roughly, within a volt or two.
Do you mean C176?????
 
Too late I already eat.
 
Enjoy your meal.

Thank you. Ain't nuthin' as good as Country Boy Caviar!

country boy caviar.JPG
 
I think I'm finally seeing it.
Pin 7 of the ignition control module comes out about 2 to 3 inches then it splices and becomes the two wires that are bear wires.
Each of the bear wires then go separate routes.

One bare wire wraps around wires 395, 929 and 259.
For how long of a distance I don't know.
I haven't figured that part out yet.

( Wire 395 is gray with an orange stripe and it goes from the ignition control module with no connections to the powertrain control module. )

( Wire 929 is the pink wire it goes from the ignition control module to connector c127 which is the spout check connector.
Continues on the other side of connector c127 it's still pink and it goes on to the power control module.)

( Wire 259 is orange with red stripe and it goes from the ignition control module with no connections to the powertrain control module. )

The other bare wire wraps around wire 349 and wire 350 for a distance.
How far of a distance I haven't figured that out yet.
Then the bear wire becomes an insulated wire once again black insulation and it's become wire 57 again. For what distance I don't know.
I haven't figured that out yet.
It goes to connector c123.
Then on the other side of c123 it continues as an insulated black wire continuing to be wire 57 for a distance.
I haven't figured out what distance that is yet either.
Then becomes another bare wire again.
Once again wrapping around wires 349 and 350 for a distance.
Once again I don't know how far that distance is.
I haven't figured that out yet.

( Wire 349 is a dark blue wire and it goes from the ignition control module to connector c123.
Then on the other side of connector c123 it continues to be dark blue wire number 349 and it goes to the crankshaft position sensor )

( Wire 350 is gray and it goes from the ignition control module to connector c123.
Then on the other side of connector c123 it continues to be Gray wire number 350 and it goes to the crankshaft position sensor. )
 
Last edited:
I've edited my post, post #550 of this thread.
I believe it is easier to read and understand.
 
Yes, you are reading it correctly, and reading it well.

Use the "Locator" information in EVTM to find the various components that are shown in the electrical schematic.

There is also a suffix the back of the manual that will quickly tell you where connectors are.
 
So this morning I untaped and took off some more of the wire casing, I think it's called a sheath.

Here's what I found.
IMG_20250314_112017165.jpg

Can you see where the shielded wires are now taped with the wires that they need to be.

I pulled back some of the tape of each of those and found:
IMG_20250314_143345212.jpg

There's foil underneath that tape.

And
IMG_20250314_143404906.jpg

There is foil underneath that tape as well.

After I found those I had to stop for a little while. My brother Kenny wanted me to come help him do some stuff.
So he picked me up and we went and did what he needed done.
Now I'm getting ready to start working on my truck again.

I will give another update later.
 
First, individual wires are covered with “wire insulation”. Multiple insulated wires grouped together are covered by more wire insulation, often called the “sheath”. This makes a “cable” assembly. In circuits where there is a chance of magnetic interference causing a problem, usually communications circuits, the wires of each channel of communication are twisted together to mitigate the effects of the interference. Then, the twisted pairs of wires are wrapped in a conductive shield, usually another set of wire strands, sometimes also covered in foil. This shield must be connected to ground, often only at one end. Grounding the shield conducts the interference signals safely to ground, protecting the communications signal and keeping it pure.

Now you know more than you ever wanted. Sorry. It happens to be “what I do” for an occupation.

See those twisted pairs of wires in your picture? Don’t untwist them.
 

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