Expert: Brad Sears - 7/6/2009

Question
QUESTION: I have a 1962 ford thunderbird . I have a new battery that I purchased last year it holds a 12.6 volt charge. Just recently my generator light wont shut off. I have opened up the regulator and lightly sanded the points. Light still stays on. I checked all of the three grounds and they re secured. I removed the field lead on the regulator and touch the b. lead a saw a brief spark.How do you check the generator while its still in the car. I have a voltmeter. Larry  thank you I have had this car for two yearsnow. One last thing I recently had a passenger side exhaust manifold replaced and used a lot of p.b. blaster to loosen up the studs and maybe some of this got down into the generator which is right below it.But its been two weeks that I changed the manifold and the generator light wasnt on then. If my generator is at fault what problems other than the light staying on.Could this also drain the battery also.

ANSWER: With the engine idling and a voltmeter connected across the battery, jump the field terminal of the generator to the a terminal. Increase the engine speed and watch the voltmeter. If you can get to 14 volts at about 1500 RPM the generator is producing electricity. The problem is probably the regulator.
Brad

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QUESTION: hi brad. When you said too jump the a field to the f field. Do I take those two  wires off first then hook a jumper across the A field and F field.And then if Iam getting 14 volts its not the generator.This generator has three poles. One has a green wire to a terminal the second below has a yellow wire to it and the third has a yellow wire behind the generator. I would thing the green wire is the ground. Your thoughts on this.  Larry

Answer
The A terminal on a Ford generator is on the back of the unit. the two wires on the case are the Field and the ground. The A wire you leave on but the F wire you can take off before you jump the terminals. The terminals on the generator are marked with an G and an F. This can also be done at the regulator and the regulator should be marked. Do not use the B terminal as that is live battery. I cannot give you a color code for this.