Damn charging system

Afternoon Brothers.

A couple of weeks ago, my alternator light came on in the dash. So, my immediate thoughts were that the regulator was FUBAR. It was a direct replacement for the original type. so, plugged it in and same as before (only difference was the capacitor plugger came apart). So, to the next step, the alternator. Field, battery & indicator light (it’s an early '67 so I’ve been following the Mustang diagrams which all show no stator). Any idea on what the heck I’m doing wrong?? Joe

What is the voltage at the battery when it is running with lights on, heater motor blowing etcetera.

doesn’t change, 12.3 no matter if anything is on or not (has dropped from 12.6 from needing just battery)

Most of the mustang diagrams show the wiring diagram with Ammeter and Cougar diagrams show the wiring diagram with idiot lights. Attached is my writeup that contains both but in your specific case use the Cougar wiring diagram.

Coach Jack
1967 Cougar charging system in depth.pdf (411.7 KB)

Most auto part stores will test the alternator for free. I would start there.

Thanks for the help. Actually, this is the 2nd alternator from NAPA. After a couple of days, I returned it and just gave me a replacement. Since then, I’ve created my own harness that also did nothing. I’ve also ordered a new alternator harness to see what I can do with that. It’s for a 65 Mustang but as I said it’s an early build (10/66 I believe). The only other piece that I’ve not changed is the condenser with the broken plug although I can’t see that as an issue

The condenser is there to suppress arcing across the regulator relay contacts. It needs to be in the circuit. Also, make sure your grounds are all solid and clean, and the engine/alternator/regulator/battery negative are all well grounded to chassis. My first 70 Cougar kept melting the rectifier diode solder joints inside the alternator causing low output. Turned out to be poor grounds.

The condenser is a non - issue, it matters not. The alternator does matter, and it is worth getting any of them tested new or not.

I bought a Napa altenator for my Subaru. This was years ago. It took a dump 9 months later.

Put in an auto zone and never had a problem after that.

Check to make sure the ground and stator wires didn’t get mixed up after the initial failure and installation of the replacement alternator. My harness doesn’t have the molded plastic to keep them straight. This puzzle took me some time to figure out when it happened to me. They are the same size lug and the stator has a black insulator I confused for ground. Wont do that again.

Also, a store bought alternator may not be “clocked” the same as the one that just came off. Always check to see it matches the old one and by all means, like Royce says, have them check the new one.

My personal policy is to have the people in the store test their rebuilt alternators and starters before I leave the store with one

That’s a good idea because most of the new ones are not any good.

Yeah, the condenser not being there won’t keep the charging system from working. But it does help suppress radio interference from regulator contact arcing.

It’s been said here before. You don’t have a Mustang. The alternator wiring is different. You must wire it and use the correct harness for the Cougar. The stator output is used in a standard Cougar.

Understood but of course I can’t find one. As for this splice, the only wire missing is the stator connection. I bought a slice for both ends

This is what you need. Might be able to find the one for Mustang with Tachometer for less.

This is what I bought:

What I see missing is the stator wire

Yes it is a different harness. It looks like the pin out is also different. I think if you get the right harness it will all still work. The uncertain part is if the voltage regulator got fried in the mean time. I would start with the correct harness and then see what you get.

thanks, i’ll get the newer one

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This is one of so many areas where Mustang and Cougar are different… It’s always a good idea to check West Coast Cougars site and see what they show. Usually if it is the same as Mustang it will show that.