03-04 145 KG3 tahoe alternator?
06-04-2013, 03:05 PM
#3
i would say at least since 1998 that the engine computer controls the alternator, I say 1998 because that's when the 4th gen started and i know about it. all alternators will have an output wire that goes to the + side of the electrical system, that's the only thing in common with them all.
Then there is a smaller plug with wires, in some cases just one wire, that plugs into the alternator and this is what controls the alternator. Many people call it the exciter wire, which is out of context given the original definition of what the exciter wire was on the old style alternators like a delco 10si.
This plug with however many wires connects the voltage regulator inside the alternator, and since 1998 they are a microprocessor. it gets connected to the engine computer and possibly other things. I know on my 2002 that it is a 4 pin plug but only has one wire going back to the computer. I don't know how many wires there were on the 1998 models but I've read that it was a 12v signal sent to the voltage regulator to command the alternator to output. later years it was a 5v signal, possibly a solid +5v, but info is vague and conflicting and my service manual also describes it as a pwm signal (pulse width modulated) to control alternator charging. so from all that an alternator can fit but it's the voltage regulator in it being the correct one to interface with the wiring and the engine computer that makes it work. use the wrong one and best case scenario the alternator doesn't charge (or maybe it does) and worst case you blow the engine computer and/or the regulator in the alternator. unless you find out that specific piece of info regarding the voltage regulator and how it's wired, you are taking your chances.
http://www.motor.com/article.asp?article_ID=1606
Then there is a smaller plug with wires, in some cases just one wire, that plugs into the alternator and this is what controls the alternator. Many people call it the exciter wire, which is out of context given the original definition of what the exciter wire was on the old style alternators like a delco 10si.
This plug with however many wires connects the voltage regulator inside the alternator, and since 1998 they are a microprocessor. it gets connected to the engine computer and possibly other things. I know on my 2002 that it is a 4 pin plug but only has one wire going back to the computer. I don't know how many wires there were on the 1998 models but I've read that it was a 12v signal sent to the voltage regulator to command the alternator to output. later years it was a 5v signal, possibly a solid +5v, but info is vague and conflicting and my service manual also describes it as a pwm signal (pulse width modulated) to control alternator charging. so from all that an alternator can fit but it's the voltage regulator in it being the correct one to interface with the wiring and the engine computer that makes it work. use the wrong one and best case scenario the alternator doesn't charge (or maybe it does) and worst case you blow the engine computer and/or the regulator in the alternator. unless you find out that specific piece of info regarding the voltage regulator and how it's wired, you are taking your chances.
http://www.motor.com/article.asp?article_ID=1606
Last edited by 1 FMF; 06-05-2013 at 12:06 AM.
