Identify these two

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peche 71

Well-known member
Joined
Aug 13, 2012
Messages
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Location
NY
My Car
1971 Grande, 351 Cleveland, restoration project
1973 Convertible, 302, slight restoration
Need help identifying where these two go. The first smaller red wire, with the yellow end, middle of first picture, is attached to the left of the voltage regulator on my 73 'vert 302, need to know where the other end goes, the wire is kinda long. (This connection is not found on my 71 351c) .The second is possible an O2 sensor? but not sure where it connects to.







 
Look at the top bar on this web page under "Mustang Data". Select wiring diagram and go for it.

I would consider pulling all that wiring out and trashing it. Get a new alternator harness and a new engine gauge harness, new battery leads. Then run it back the way it came. That thing the red wire with the yellow terminal on it is not stock I believe. Its not on my 71 either. Might be some kind of thing someone wired up for electronic ignition or something. Either way I would check the 73 diagrams above, and rewire it back to stock as a start.

Basically you have 3 wires plus the charge cable coming off the alternator.

Red Charge wire goes to the side of the starter solenoid that the battery is connected to.

The black wire grounds from the alternator.

the Yellow wire goes from the Stator output on the alternator to the S terminal on the voltage regulator. ( I dont think this wire is used on our cars with factory gauges.)

The small red wire is the field output. it goes to the F terminal on the voltage regulator.

check out this thread.

https://www.7173mustangs.com/thread-rear-wiring-on-alternator-1971-351c

 
Last edited by a moderator:
Great info, thanks. So the speed cable connects to …?

 
That end connects to the back end of the transmission. There's a hole in the side of the transmission that it goes into, and there's a "U" shaped bracket and bolt that holds it in place. There's some reason that it's not already connected, I would try to figure out why.

I would also turn the gear by hand to make sure it turns easily. You'll also want to clean it before you stick it into the transmission. If the transmission has been setting for a while with the hole open I would also try to clean it. Hard telling what may have crawled into it.

 
Someone disconnected that speedometer cable for a reason. When you hook it back up, drive it around. If the gauge bounces at low speed, then you need a new cable. They make them, so its not a big deal to find one.

 
Here are a couple of good videos showing info on the speedometer gear and cable.



Make sure to check the drive gear on the tailshaft, up in the hole, it may be stripped and need replacement, hence the reason its disconnected.

 
Here are a couple of good videos showing info on the speedometer gear and cable.


thanks much, great info. it's always something! I discovered there's no fuel line from the carb to the fuel pump. and just like my 71 I need a new ignition cylinder and ignition switch.

 
Did you ever figure out what that red wire near the starter solenoid was for?
not yet, there's no factory add- ons like an EFI, or running lights etc

 
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