Engine bay wire id please

[MooseStang]

On my L code project, I've got 3 wires I don't know what they are. The first two are passing through the firewall, one right of the vacuum lines, and the other with the main harness group.
The third is near the starter solenoid.

 

[Steve McMahan]

This diagram is a work in process, so understand it is not the end all of 73 wiring diagrams, although, when I needed help, it was very useful.

If you look closely, that one wire in the first attachment looks to be part of the emissions control system. On my 73, it looked very similar.

I’m not sure what the second attachment wire is for, because I cannot determine from your description where it is; need more context to help. Steve.

 

[Doug's 73 Mach1]

The 2 wire lead sitting on the air cleaner is for emissions, they connect to an EGR cutout solenoid (if equipped, used with 351 2v and 4v) mounted on the front corner of the driver side valve cover that Steve mentioned. The other wire coming out of the fire wall (brown, yellow dash) connects to the transmission T.R.S. switch (if equipped, used with 250 CID engine only). The one by the voltage regulator could be a yellow wire with white stripe (hard to tell) that connects to the Alternator wiring harness that in turn connects to the radio noise suppression capacitor mounted below the voltage regulator.

Doug

 

[MooseStang]

Thanks for the replies. One more question. While adjusting my reverse lock out rod, I noticed wiring in front of the shifter rods. What is that?

 

[MooseStang]

Brown, green & red.

 

[Doug's 73 Mach1]

The green and red (pink with white dash) are for the seat belt warning switch. The brown with yellow dash for the emissions related T.R.S. switch. This assumes you have a 250 CID engine with a manual 3 speed transmission.

 

[MooseStang]

Yep, this is on my 6cyl 3sp manual. Thanks again for the help.

 

[mrgmhale]

Dang Doug! You nailed each and every item you spoke of. I just now saw this post and downloaded the schematic to see if I could make sense of it, and perhaps impart some information. Then I took note of your responses. I think I will look at the schematic anyway, now that it is downloaded, and see how it differs from my other schematics for 1973 Mustang (both electrical and vacuum schematics from Forel Publications).

Anyway, well done my friend...

 

[mrgmhale]

View attachment 66644
This diagram is a work in process, so understand it is not the end all of 73 wiring diagrams, although, when I needed help, it was very useful.

If you look closely, that one wire in the first attachment looks to be part of the emissions control system. On my 73, it looked very similar.

I’m not sure what the second attachment wire is for, because I cannot determine from your description where it is; need more context to help. Steve.

Steve, I am interested in where you acquired the schematic you shared from. I have nearly all available vacuum and electrical schematics available from Forel Publications, and from Mustang Barn (67-72 engine vacuum calibration schematics). And the schematics I have in PDF files from those two sources are pretty decent, especially for electrical 1972 & 1973, and vacuum schematics for 1973. But, I am always on the lookout for different kinds of schematics in case there is anything incorrect or missing from the ones I have. Could you please let me know from whence you acquired the one schematic you shared in this thread?

Following is the graphic I have for calibration 3-14A for 1973 351C 2v. The information is (also) good, but the layout is done in a far different way as compared to your schematic. And it is purely vacuum related, nothing electrical. I have the full electrical schematic from Forel also, but it does not present aa schematic that involves only emission control related circuits. It is a good schematic, but I find the one you provided is a bit easier to follow.


Thank you.