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George H.
George H., Technician
Category: Classic Car
Satisfied Customers: 18701
Experience:  Old enough to have worked on them when they were new
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Having problems getting my two post aftermarket amp gauge to

Customer Question

Having problems getting my two post aftermarket amp gauge to show that the car is charging
Submitted: 1 year ago.
Category: Classic Car
Expert:  George H. replied 1 year ago.
Hello I will help you with your question, Do you have the brand and part number of the gauge? How is it wired now?
Customer: replied 1 year ago.
Customer: replied 1 year ago.
That's how it is wired now and it will drop negative off 0 when I am starting the car but won't show that it is charging once running
Expert:  George H. replied 1 year ago.
Does the "to alternator" run straight to the alternator B+ post? Is there another cable between the alternator and the positive post of the battery?
Customer: replied 1 year ago.
There is a smaller wire that runs from the positive to the stud on the alternator
Customer: replied 1 year ago.
And I am pretty sure that the wire I am using runs into the plug on the alternator
Expert:  George H. replied 1 year ago.
This is a very dangerous type of gauge that was phased out long ago as all the charging/discharge current runs into the cabin through the gauge and back out. It is a direct wire to your battery if the wire is damaged. If there is a second wire between the alternator B+ post and the battery positive remove it and see if the gauge reads properly then. Thanks
Customer: replied 1 year ago.
What gauge do you recommend?
Expert:  George H. replied 1 year ago.
For the wires to the gauge? OR what would I replace this with? If the latter it would be a voltmeter type gauge that will monitor battery voltage when the key is in the run position. They take lighter wiring and don't have the problem of a direct wire to the battery does. They shut off with the ignition switch. Please let me know how I can help Thank you
Customer: replied 1 year ago.
well I did just buy the gauge with a set of three so I would have a hard time matching them up if I get a different gauge and if I put a battery tester on the battery it says it is charging at 14 volts here is a picture of the gauge
Expert:  George H. replied 1 year ago.
The gauge will read charging amperage. It is just the wiring to it has to be heavy gauge (meaning you have to be able to run 60 amps through it safely) and that is the danger. If you had a voltmeter I would go back to it. This is an Ampmeter. Let me know what I can do to help you with this Thank you
Customer: replied 1 year ago.
So how would I hook up a volt gauge?
Expert:  George H. replied 1 year ago.
A volt gauge would be from a switched 12 volt source to the gauge and from the gauge to a good ground. Back at the battery would be best. For the illumination you want the gauge wire from the present cluster, I can help with the location if necessary.
Customer: replied 1 year ago.
Ok well I am going to order a different three gauge set up with a volt meter I will respond back to you if I have any trouble thanks
Expert:  George H. replied 1 year ago.
Great, I am always glad to help Please let me know if you have further questions Thank you

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