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'65 Alternator Wiring

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I have a yellow wire connected to the STA terminal on the back of the alternator.

Looks like the villainous PO set it up. I added the other wire that runs to the choke [on the SUM MV2008].

Going to a MC solid state voltage regulator causes the ALT light to flicker.

Any troublshooting help would be appreciated.

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Not the point. 66-up all had the internal cap. But not 65. His new wire will have the plug. Any radio-equipped 65 would have the cap. If he has a replacement alternator, sure, it'll be sure to have the internal cap, but it would cause no harm to have the external cap, too.
True dat. I did notice, in a photo, that he had a Motorcraft case so....
 

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Discussion Starter · #22 ·
@22GT correct. New harness has a plug for it but I’ve not put in the capacitor-at the alternator nor at the VR.

Alternator is a replacement (has Motorcraft embossed on the back).

I notice you are missing the static suppression condenser. They are available in nice repro. That's a 65-only item. The new harness should have a plug for it.
 

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Discussion Starter · #23 ·
Good morning.

So new Motorcraft branded VR = flashing ALT light on dash
Old mechanical VR = NO flashing light on dash

At idle, the volt reading is spastic for both VR's.

Perhaps an alternator problem?
 

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Shot in the dark.... unplug the IVR (instrument voltage regulator) and tell me what happens. Perhaps the instrument cluster is not properly grounded?
 

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IVR unplugged = no ALT blinking.
Check your instrument cluster and engine to firewall grounds. The cluster grounds through tabs that contact the 2 lower mounting screws. You might try a dedicated ground wire between the IVR mounting screw and the metal dash structure. Also check the continuity of the ground between the voltage regulator and radiator support.
 
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