Wire identification help (1 Viewer)

[78GroundUp]

Ah Grass Hopper! , that is the transmission position switch. It goes directly to the emission control computer. You can find it in your schematic if you locate the ECC. It is right under it. I will try to post the schem. in a couple of minutes.

Can you teach me what transmission position switch does....?

Also: those two misc wires are throwing me. When everything is connected. Those two still hang free?(unconnected) I will attempt again to learn how to use a wiring schematic... They confuse the s*** out of me..... Thank you.

I will try to get better pics tomorrow of the random wires.....

 

[78GroundUp]

additional info

OFF got two wires I can't seem to identify. Done pretty well with everything else. Thanks to y'all.

Wire on left is riding in main rear harness. Just hanging out there.

The wire on the right is coming of the "finger" or "splice" leading up to reverse light connection, seatbelt, fuel sender, etc........

They both appear to have 30 years worth of mud, dirt, debris. When I bought the truck it did not have a rear heater at the time. Makes me wonder if it's heater related? That said, they are also far enough apart that they might not be related at all....

I have looked at many different wiring schematics. I conclude I am not smart enough to figure those out, or this wiring dilemma.

Thanks ahead of time.

I dug up this... and seems to identify but not accomplish anything. Hopefully someone will recognize what they are? or why they are?? Thanks for the help in advance.

The two wires I am indicating in the original thread before it digressed to other stuff or numbers 103/104. Mine like his are 'unused". Were these ever used for anything? Thanks for the help

This is his function list:

Rear Harness

101 - Underhood main connection on firewall
102 - Underhood main connection on firewall
103 - Unused
104 - Unused
105 - Reverse light switch on trans
106 - 4th gear position switch (Not used on 79?)
107 - 4th gear position switch (Not used on 79?)
108 - Frame ground
109 - Fuel tank ground
110 - Fuel tank sending unit
111 - Seat belt warning connection - driver's side
112 - Rear passenger tail light
113 - Rear passenger marker light
114 - Rear license plate illumination (?)
115 - Rear driver marker light
116 - Rear driver tail light

NOTE: The number indicated in the rear harness photo corresponds to my 1978 harness. Mine may not be original.

 

[78GroundUp]

Got it figured out... guess it has something to do with the emissions knowing when I am at hwy speed or something?? but all clear there. Thanks for the help Platy... much appreciated.

 

[poptartz]

Nope not on transfer..... So I get.... Although this is off topic from my original thread it is part of the problem solving equation ..... If this is an indicator sensor(?) where/what does it indicate? Etc.... 5/78 - FJ40

This wire tore off while I was installing the tranny yesterday. I don't have any smog parts on my truck, so do I just forget about this one (the single wire on top of the tranny pointed at in in post #16 with the red arrow)?