Alternator Wires

[bobcostas]

Hey dudes.
I'e been having a charing issue with my alternator or a while. I was wondering if anyone knew what the two regulating wires are. I know where they go, what what do they "do"? there is a white or black wire, and a blue wire.

gracias!

BC

[raycow]

This is a diagram for a Buick, but the connections are the same for all of the externally regulated alternators. Blue is power to the field and white is power to the field relay coil once the alternator begins charging. When the relay contacts close, the warning lamp goes out.

http://www.rowand.net/shop/tech/imag...-1970Buick.jpg

Ray

[bobcostas]

thanks ray!

do you know what voltages i should be getting on either?

[hossmann]

swap it out for an internaly regulated alternator thats what im doing because there is a reson they quit putting them on cars and trucks

[raycow]

Sorry, I can't help with voltage specs, although that info might be in the shop manual.

All I can say is that there should be "some" voltage on the blue wire with the engine stopped and the switch on, or else the alternator will not begin to charge once the engine starts. With the engine running, there should be voltage on both wires.

Perhaps it might help if you tell us what specific problem you are trying to fix, and what voltages you are measuring under what conditions. One test you could run is to connect the blue wire to battery voltage and see what happens (a jumper at the regulator end might be easiest). Do this at idling speed only, and for no longer than it takes to get a voltage reading, because this effectively runs the alternator at full throttle and isn't particularly good for the battery either.

I have had an externally regulated alternator on this truck for about 10 years now with no problems. If and when it does die, I will probably replace it with an internally regulated one, but this is only because of parts availability and cost. Btw, you can now get a solid state replacement for the mechanical regulator. With one of those, reliability should be at least as good as with the internal regulator and maybe better, because it will be subjected to less heat.

Ray

[bobcostas]

Excellent. i will fiddle with it this afternoon.

it seems my battery is not charging. i have replaced all three components (incrementally starting with the cheapest) and still no dice. i only get ~12.3v when idling and it drops by about 0.1v after every commute. and now i have a lifetime warranty on the externally regulated alternator, so replacing that with a newer one is a waste

thanks dude