electrical questions
Thread Starter
Melting Slicks
Joined: Feb 2006
Posts: 2,092
Likes: 5
From: Fayetteville Arkansas
electrical questions
So before, if no one remembers, in my 1972 coupe, small black 350 4 spd, the previous owner had accidentally switched the polarity on the battery when changing it out for a new one. The results was some fried wires.... from the fusible links all the way to the horn relay. So now, new starter solenoid, new negative battery cable, new alternator, new engine wire harness, new front lighting harness, new ignition switch, new lock cylinder. Car started... but the amp guage doesn't move ever.... stays pegged in the negative... doesn't move on start up nor rev nor idle. When i checked the battery it read 11.6 amps and then at the alternator it read 11.6 amps... could it just be that the alternator is bad and not putting out any power? How do I test the ameter guage to see if it is workinng or not?
Thanks guys,
Sully
Thanks guys,
Sully
Burning Brakes
Joined: Mar 1999
Posts: 1,047
Likes: 3
From: CA
If you have a volt meter connect it to the battery. When the car is off the reading should be > 12 volts and when running it should be in the range of 13 to 14 volts. This test should rule out whether or not the alternator is working. Maybe your guage blew out when the prior owner connected the battery wrong. There is a guage on the back that has a resistor across it...dont remember which one though.
Thread Starter
Melting Slicks
Joined: Feb 2006
Posts: 2,092
Likes: 5
From: Fayetteville Arkansas
Nope my battery and the alternator aren't reading that... lower elevens... I think I am going to pull the battery and alt and take them both down to Autozone for a bench test and then pull the amp guage and test it seperately...I don't want to take a chance of something burning up...
Sully
Sully
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
If there are only 11.6VOLTS at the battery and the alternator with the engine running the alternator is definately not working. There is a plug on the side of the alternator with 2 wires. 1 is switched 12v from the ignition switch circuit, that is the voltage sensing line for the regulator. The other is the return side of the idiot light in the dash, it provides field excitaton for the alternator. Check for voltage at both of those 2 points
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Thread Starter
Melting Slicks
Joined: Feb 2006
Posts: 2,092
Likes: 5
From: Fayetteville Arkansas
ok im going out to the garage
took the afternoon off using the excuse of "it's my birthday!" I am going to figure this thing out on my car or get a new alternator!!!
Wish me luck, and yes I am taking the laptop out to the garage too! I need it to follow the diagrams you guys (sixfooter) sent me.
Sully
Wish me luck, and yes I am taking the laptop out to the garage too! I need it to follow the diagrams you guys (sixfooter) sent me.
Sully
Instructor
Joined: Apr 2002
Posts: 210
Likes: 0
From: parsippany nj
A simple test for the gauge would be to turn the ignition switch to the on position without starting the car. Turn on your headlight s and see if the gauge moves to the discharge end. If it does, the gauge is probably working.