faint glow-battery light?

[Rick Garrett]

When my 82 is running (lights on and off) the battery light has a faint glow? The light seems to work fine, it comes on when car key is in ignition and goes off after starting. Any ideas why this is happening?

thanks

[Joe Fisher]

Re: faint glow-battery light?

Rick, if you say the light comes on with the key on and the engine off, more than likely you have an alternator problem. If you have a voltmeter, start the car, and get the light to glow. On the alternator two wire plug, one wire should be red, the other wire is thinner and I think it is brown. With everything connected, probe the red wire, it should read battery voltage, 14-14.5v, then probe the brown wire, if you have a lesser voltage, say 10-12v, then the diode trio in the alternator is defective. It can be replaced very easily. The parts are easy to come by. Joe

[Robert C.]

Re: faint glow-battery light?

I believe the battery is not charging ALL the way up. Have it tested or recharge it and see if the dim light is still there. I bet not!


Texas Chapter NCRS

[Bill Clupper]

Re: faint glow-battery light?

The light turns off when an equal positive voltage is applied to both sides of it. a faint Light indicates a small imbalance in the voltage. Check wiring connections or alternator output

[Scott C]

Re: faint glow-battery light?

Most likely you have a defective diode in the alt. Do check its output first to confirm this. As one of the postings states, equal voltage at both sides of the lamp are required to 'turn it off'. A defective diode will cause the alt to put out insufficient voltage to accomplish this. A DIY repair would be the cheapest route, and allow you to retain orig alt. You can also clean the unit, and check the brushes for excessive wear and check that all connections are clean and tight. Read service instructions carefully, as it's one of those repairs that can be difficult the first time on reassembly.