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Wire diagram glitch

Mach1 Driver

Well-Known Member
Hey Midlife, I need your help again!
There is a vacant place on one of the pages of my 69 Mach wire diagram. When I look on-line the diagrams are too blurry to read. There are 4 wires converging on this area and I don't know if they somehow cross or connect.
They are all in the engine compartment and the wires are:
a. Coming from B+ to a splice near the starter relay is wire 38A (probably Black), the other end connects to?
b. 38 Black coming from the center wire in the alternator plug and the other end connects to?
c. 37 Black/Yellow coming from the firewall plug (the big boy) and the other end connects to?
d. Coming from the Ammeter, through the firewall plug wire 654 Yellow then connects to?

Trying to make sense out of the circuits it looks like 38 Black and 654 Yellow connect together, while 37 Black/Yellow and 38A connect.
If I verify this I can finish and post a complete car schematic for a 69 Stang. Thanks for your help.
 
38A is the line from the battery starter solenoid to the OEM splice. 38A is black.
For the standard dash (ammeter present) configuration, the OEM splice has three break-outs:
38A goes to an OEM splice halfway down the line to the large pin on the green connector block that mates to the fuse box, but changes number to 37 after that second OEM splice. More on that second OEM splice in the middle later.
655 (red) goes to one of the ammeter leads at the same green block connector
152 (green/black) goes to a pin on the voltage regulator.

The OEM splice half-way down on 38A/37 also joins two other lines:
654 (yellow) the second ammeter line, which registers the alternator output
38 (black) which goes to a 3 prong plug that connects to the alternator. This line represents the alternator output, and feeds the battery through this line, and back up to the first OEM splice mentioned.
 
38A is the line from the battery starter solenoid to the OEM splice. 38A is black.
For the standard dash (ammeter present) configuration, the OEM splice has three break-outs:
38A goes to an OEM splice halfway down the line to the large pin on the green connector block that mates to the fuse box, but changes number to 37 after that second OEM splice. More on that second OEM splice in the middle later.
655 (red) goes to one of the ammeter leads at the same green block connector
152 (green/black) goes to a pin on the voltage regulator.

The OEM splice half-way down on 38A/37 also joins two other lines:
654 (yellow) the second ammeter line, which registers the alternator output
38 (black) which goes to a 3 prong plug that connects to the alternator. This line represents the alternator output, and feeds the battery through this line, and back up to the first OEM splice mentioned.

OK, thanks I put that in the attached .pdf so you could see what I think you said.
1. Did I get it right?
2. If so do you notice that wire 38A effectively shorts out the ammeter? Unless there is some significant resistance in 38A, or the ammeter is super sensitive, it shouldn't work.
 

Attachments

  • MUSTANG WIRES.pdf
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That's a common mis-conception of wire 38A shorting out the ammeter. Consider it this way:
The two legs of the ammeter measure the voltage differential between the two points. Normally, they would be the same (to first order that is true), but the resistance of the yellow wire is higher than the thicker wire, so there is a voltage difference at the two points due to the resistance of the bigger wire vice the thinner wire. Think of the ammeter as a very sensitive volt-meter.
 
Well then its a volt meter? Its measuring voltage, not current. I'm trying to envision how that goes positive and negative (charge vrs. discharge). Hmmm.
So you didn't really answer the question about the wire diagram, but given the connection of the ammeter that infers that 38, 38a, 37 and 654 all go into one splice?? There is a blank area on my diagram where they converge.
 
38, 38A, 37, and 654 are OEM spliced.

Thanks Mid. I think I'll take the wiper motor apart, or at least do some testing to verify how it operates, then I should be ready to post the schematic of the car. 37 pages condensed down to about 3.5.
 
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