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I'm looking through my Haynes manual (specifically page 12-54) at the wiring diagram of the engine compartment, 92-later.
I see a diagram symbol I don't recognize.
Picture 3 parallel lines, where one has a dot in it and where the dot is, there is a dotted circle around all 3 lines.
Is this the symbol for fuseable link?
It's marked with "NCA" on both ends of the line, this line doesn't connect to the others, only has this dotted circle.
Anyone know what it means?
Also, in regards to ground wires...this book will say like "ground B" for the ground pins on the computer, but I don't know where exactly "ground B" is on the truck, and don't see a listing in the book.
I think it's the ground on the radiator support infront of the coolant/washer tank but I'm not totally sure.
i ust looked and there is another ground on the other side of the rad,pass side.i ditched the core support long ago and am going by memory as to where they attached.we didnt move them very far from the original placement.
Well I got the ground B figured out - on another page it lists the grounds and then you can find them in the diagram and they tell you where it is. I think ground B is over by the battery.
That isn't really the big deal though, I'm more interested in what that electrical symbol means.
I agree that it's showing a shielded set of wires. The line with the circle and the dot is the shielding, and the lines within the circle are the wires that are being shielded. Are they regarding the TFI circuit? I know that is shielded on my truck, not sure about yours though.
It is ignition related. It starts from the distributor.
There's two of those symbols, one about 1" from the distributor in the diagram, which that dotted circle covers the pip wire and the ignition ground wire. Then on the other end of this NCA wire, is another one of those symbols which again includes the pip and ign gnd, but also has the SPOUT in it too.
Sounds like what you're talking about Eric.
I don't know what exactly is ment by "shielded wires" - and what that is all about.
"NCA" means "No Color Assigned" since it's an uninsulated (bare) wire wrapped with the twisted, insulated pair for the PIP module. Around all three wires (the two twisted insulated wires and the bare wire) is a foil shield, which makes physical contact with the bare wire here and there along the length of the assembly.
The symbol in the diagram technically is incorrect, it should illustrate that it's twisted, but whoever did these diagrams was a lazy SOB. But know they are twisted... about 60 twists per foot, give or take.
Like so (I circled the symbol in red):
BTW, when making a harness from scratch, making a foil-covered twisted pair is a real pain in the ***!
Last edited by frederic; Mar 22, 2006 at 07:07 PM.
I don't know what exactly is ment by "shielded wires" - and what that is all about.
The shield on those wires is to protect against electrical interferences. This type of sheild is used around wires that carry a very low current/voltage, and can be easily disrupted by an outside interference.
The shield should ONLY be grounded at one point. Having it grounded at more than one point could complete an electrical path, induce current flow and interfere with the signal being transmitted on the conducting wires (wires within the dotted loop). A break in the insulation could cause this if the shield should come in contact with a potential grounding point.
Last edited by Blurry94; Mar 22, 2006 at 09:44 PM.