My Gen light blinks on and off about every second at low rpm's. Volt meter needle twitches slightly to the same beat. (stereo is off) I have checked all wiring connections, as suggested in a previous post, and they are fine. Belt to alternator is tight. One possible clue is when the head lights are on, it does not do it.

What is causing this?


Oh, is it an alternator or a generator? If an alternator, why does the light not say ALT, instead of GEN?

 

What are you calling low rpm's? May be idle is too low?

 

Here's some information that might help (actually just learned this over the weekend while troubleshooting a similar problem on my car).

The GEN light has two positives coming to it, as opposed to a normal bulb. One of the positives comes from the same voltage that is supplied to the voltmeter, the other comes from a reference line in the regulator (which is in the alternator case).

When the system is fine, the voltage produced at both leads is identical. Since voltage is a potential difference between two leads (most commonly from positive (12V) to ground (0V)), if the system voltage is different than the reference signal, the difference is the voltage that the lamp perceives, which is why it comes on dimly when the system is starting to fail and then gets brighter).

When you have the ignition on and the car is not running, the voltmeter lead has a + 12 volts or so, the reference line has no voltage, so the lamp lights up. Once you start the car, the voltage on the reference line kicks in and there is no difference (or voltage) experienced by the lamp and it goes out.

If it is coming on at idle and pulsing, it could b ethat the regulator in the alternator is failing (which was my case). I was able to buy just the regulator and replace it in the alternator case. I got mine at Autozone and it cost about $20.00. It's pretty straightforward to dissasemble the alternator and replace.

 

It's your regulator, built into the alternator. These are not hard to replace, but you do need to dis-assemble the alternator to replace it. Plan on replacing the brush pack and both bearings while your in there, and you will have an original #'s rebuilt alternator!

Hans

 

Its an alternator. They probably stuck with generator since most people will understand it.
And in the end an alternator is a generator.
The generators at work are alternators but no one calls them alternators, just generators. 50,000ish kilowatt generators.]
Its one of those odd things.

 

Thanks SLVRSHRK, very informative! Thanks to everyone else too, I am off to the auto parts store, like I know what I am doing.