3G alternator warm with key on, engine off

Well, that was about worthless. They can only test for stock amp rated alternators. I told them it was for a 89 5.0, and they can only test for 95 amp. It failed every test, which I was told because its not a stock amp alternator.

I checked again and I have it wired correctly.

Originally posted by 1988turbotbird:
I told them it was for a 89 5.0, and they can only test for 95 amp.

Tell them it's for a '94 Mustang Cobra. They have a 130-amp 3G stock.

Maybe you should try sending Jeff K a PM about it. He wrote that article and can probably give you some better advise.

Ahh good call on the 94 cobra. Yep ill take it back And have em test it under that if this turns out ok, ill pm Jeff and see what he thinks

I do not have first hand experience with this, but I would think that the alternator getting warm with the key on would not be that odd.

The voltage regulator is excited (turned on) by the ignition feed. It then controls the ground voltage to the windings. The more voltage (varied by control the ground) that goes into the field windings, the more voltage is created, and output to the battery. It is just a large electromagnet. If the alternator is not spinning, the fan is not moving any air across the windings, and the heat created by energizing the field windings will build up in the case.

This is assuming that there is not an RPM sense wire, which usually you only see on the vehicles with the voltage regulator build into the ECM/PCM.

Again this all in theory and based on conjecture...

-Shane

Right, my dad was saying the same thing about it probably being normal. Who all has 3g's on their cars here? Do yours get warm with the key on?

So, this is a normal operating thing. I had the key on for about 2 hours or so, I was just freaking out over nothing!