1969 Alternator Electrical Help Needed

[Jeffrey S.]

I have never been able to read a wiring diagram well and follow the path of wires so I am asking for help. There are two wires coming from the voltage regulator/alternator out of the flat connector- a large red and a 20 guage brown. What does the small wire service/where does it lead? I had some trouble with the charging on a cruise down Woodward Saturday evening and I found that both of these wires were loose in the connector. I can re-crimp both to the connector easily (I have the factory style crimping tool) but I want to understand where the small one goes so I can see if the wild swing of the ammeter from minus 40 to plus 40 was caused by the loose connections or is the voltage regulator done for. Thanks for your help.
Jeff

[Terry M.]

Re: 1969 Alternator Electrical Help Needed

Jeff
The "small" Brown wire is the feed to the field winding. It controls the current output of your alternator. If loose it will cause exactly the voltage swings you saw. Not to complicate things too much (I'm trying to keep it simple here. Those of you with EE degrees can go into the rabbit hole if you wish.), but the meter that reads "amps" is really a voltmeter. It just reads "Amps" on the face.

Good connections at both ends of both wires are essential for proper battery charging and system operation.

[Jeffrey S.]

Re: 1969 Alternator Electrical Help Needed

Terry, Thanks for the advice. That brown wire slipped right out when I went to unplug the terminal. I will re-crimp it tomorrow. Unfortunately the terminal disintegrated when I took the wires out of it. Got a new one this evening. I do understand that it is not an "ammeter" but all I care about is that the nedle stays somewhere close to the "0" mark.
Jeff

[Mark E.]

Re: 1969 Alternator Electrical Help Needed

It's not an amp or volt gauge. The "Battery" gauge reads the voltage difference between the battery (measured at the starter) and the alternator. Voltage higher at the battery/starter than at the alternator shows as a discharge, and vice versa.

Why a battery gauge? My guess is it simulates an amp guage without the need for the heavy wiring to/from the gauge. I think a voltage gauge would have been just as cost effective yet more informative.

[Terry M.]

Re: 1969 Alternator Electrical Help Needed

It's not an amp or volt gauge. The "Battery" gauge reads the voltage difference between the battery (measured at the starter) and the alternator. Voltage higher at the battery/starter than at the alternator shows as a discharge, and vice versa.

Why a battery gauge? My guess is it simulates an amp guage without the need for the heavy wiring to/from the gauge. I think a voltage gauge would have been just as cost effective yet more informative.

Right you are Mark. I oversimplified to the point of error.

Sometime in the later C3 era they went to an actual voltmeter -- a much simpler circuit.

[Jeffrey S.]

Re: 1969 Alternator Electrical Help Needed

Terry & Mark,
Follow up- I re-crimped the factory terminals and put on a new plastic plug and all seems to be good. Took the car for a drive this morning and the battery gage normalized at "0" and when I put the lights on there was no wild swing in either direction, so for now anyways, all is good. Thanks for your input.
Jeff