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Afternoon. I am new to old Fords and bought my Cat a couple of months ago and I am now on alternator number 3. I have wired it exactly like it was when I took the first one off, but I am assuming I missed something. The PO has added several relays for various components but I have yet to trace all of them, electric fan and electric fuel pump are the two I am sure of at the moment. My question is this.. I have read about a conversion to 3G, but I have no idea what that is, and there is mention of one wire conversions. I have replaced the voltage regulator with one from NAPA, but the alternators have all come from Autozone because the PO bought the one from there and it was still under warranty so I am not out that cost yet. No charge at the battery when the Cat is running and voltage steadily drops until the car dies. I have checked resistance on the wiring harness, and everything is good. I have no idea how to tell an internal regulator alternator from one that requires an external alternator regulator because everything I have ever owned was original so no need to check for modifications. (And I have only had Chevy's until now). Any help would be appreciated, I am very confused and want to drive the car. Could I seriously have received three bad alternators in a row? Or am I killing them somehow with all the relays? I have avoided Fords because the electrical always seemed a little squirrely, and this situation is only confirming my thoughts about Ford wiring. Scratching my head.
 

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I know this is not the best picture of a Ford Alternator, but it is the best I have handy.

Personally I have never had big problems with Ford electrical systems, MOPAR yes. I'm thinking it may have been wired up wrong. What year and model is your Cougar?
 

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There are a few things that commonly go wrong with these cars. One very common problem is a corroded or broken wire at the voltage regulator harness. Inspect that connector carefully for defects and broken wires and corrosion. If you find any of those problems NAPA sells a replacement connector for less than $10 with about 6" of wire so it can be spliced in and then the black harness cover will hide the splices.

When you replace an alternator the first thing to do is have the old one tested to see if it is actually bad. Any auto part store will do this free of charge. They also will test the new one to make sure that you are not wasting your time swapping good parts.
 

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Discussion Starter #4
I know this is not the best picture of a Ford Alternator, but it is the best I have handy.

Personally I have never had big problems with Ford electrical systems, MOPAR yes. I'm thinking it may have been wired up wrong. What year and model is your Cougar?
My Cougar is a 1969 XR7 Convertible. It very well could have been wired up incorrectly before I bought it. Maybe that's why they were selling it, I don't know. I have wired up the new alternators exactly like the first one I took off, so that very well could be the problem. I am not well versed in reading electrical schematics yet, but I have a feeling I am about to learn.
 

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Discussion Starter #5
There are a few things that commonly go wrong with these cars. One very common problem is a corroded or broken wire at the voltage regulator harness. Inspect that connector carefully for defects and broken wires and corrosion. If you find any of those problems NAPA sells a replacement connector for less than $10 with about 6" of wire so it can be spliced in and then the black harness cover will hide the splices.

When you replace an alternator the first thing to do is have the old one tested to see if it is actually bad. Any auto part store will do this free of charge. They also will test the new one to make sure that you are not wasting your time swapping good parts.
Ok, I will check the voltage regulator harness. I did have the old one tested, which was bad, before I bought the second one. It however, was not tested before I took it home and put it on the car, but once the car kept dying and I had the second one tested, it tested bad. I haven't taken the third one off yet because I was hoping I might have missed something even though I am wiring them exactly like the one I took off. I know there is no charge to the battery. When the car is running, a multimeter on the battery is steadily showing a drop in voltage until the car dies. I don't know how to test an alternator with a multimeter other than checking to see if there is a charge at the battery. I checked the resistance of the black wire that runs to the starter solenoid and it showed good, no breaks. Same for the ground. I didn't check the voltage regulator harness, so I will do that next. Any tips or precautions with the external regulator? I don't want to compound the problem. On a side note, I did have to replace the ignition tumbler. It literally fell out of the dash in a million pieces. Could that be a source of the problem? I didn't have any problems other than fitting my hand behind the dash, but could I have knocked something loose? The car ran after I did that, but I don't know if I was running on battery only or what. My ammeter has never worked as far as I can tell, no movement either direction when everything is on, so I figure it doesn't work. Thanks for any help. It is appreciated.
 
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