HELP!!! With My Alternator!!
Thread Starter
Melting Slicks
Joined: Feb 2002
Posts: 2,625
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From: Cut n Shoot TX
HELP!!! With My Alternator!!
I installed a new 100 amp chrome alternator today that I bought of of Ebay about 3 monthys ago. The problem is when I started the engine, my Gen light came on. It is not really bright and as I rev the engine it gets dimmer, but none the less it is on. The voltage gauge shows that it seems to be charging. It is showng about 14 1/2 volts. Why is the light on, and how do I get it to turn off? The new alternator is exactly as my old one with the same connections that I carefully re hooked up on the new one. Please HELP!!!!!!
Thanks in Advance
Thanks in Advance
Melting Slicks
Joined: Oct 2002
Posts: 2,865
Likes: 1
From: I may be getting old but I refuse to grow up
Originally Posted by VettePower
How do I replace this diode trio, and where would I buy the part???
Steve
Thread Starter
Melting Slicks
Joined: Feb 2002
Posts: 2,625
Likes: 0
From: Cut n Shoot TX
Can I get the back of the alternator off and get to this diode without taking off the pulley? I am thinking I could get the diode out of the old alternator I took off.
Thanks in Advance
Thanks in Advance
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Instructor
Joined: Jul 2004
Posts: 210
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From: Missouri
Diode trio is bad but while your in there you might as well replace the regulator and chk the brushes and bearings. You need a stout wire to hold the brushes in place when putting it back together. Also note which screws have insulators and where they go in the brush holder/regulator assembly. I can take one apart and do this in about 10 mins max but I do it for a living. 
Instructor
Joined: Jul 2004
Posts: 210
Likes: 0
From: Missouri
Originally Posted by VettePower
Can I get the back of the alternator off and get to this diode without taking off the pulley? I am thinking I could get the diode out of the old alternator I took off.
Thanks in Advance
Thanks in Advance
It might save you a ton of time and money. Most places won't put a new reg in which is usually the reason 90% of maj rebuilders stuff is crap. All they are thinking about is profit and not you getting stranded again.
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
I can tell you from experience that reversing the two regualter input wires will give you that symptom, everything else appearing normal....
to check if this is the case, with ignition off, check the red wire at the alt regulator input....it should have 12 volts on it, and be on the MOST CLOCKWISE terminal viewed from the rear of the alternator.....the brown wire should have NO voltage on it...start the engine, BOTH wires should have same 12 volts on them....
the lightbulb has 12 switched volts on one side, and if the alt fails the reg is supposed to ground that lightbulb lead, so if the ignition is off, there is NO voltage at that lead...or the lightbulb could be bad too, but if it's dimly lit, and the leads are reversed, the lightbulb is in series with the voltage sensor wire, which is allways hot normally, so it's switched off, and there is your clue in my first test there....
GENE
to check if this is the case, with ignition off, check the red wire at the alt regulator input....it should have 12 volts on it, and be on the MOST CLOCKWISE terminal viewed from the rear of the alternator.....the brown wire should have NO voltage on it...start the engine, BOTH wires should have same 12 volts on them....
the lightbulb has 12 switched volts on one side, and if the alt fails the reg is supposed to ground that lightbulb lead, so if the ignition is off, there is NO voltage at that lead...or the lightbulb could be bad too, but if it's dimly lit, and the leads are reversed, the lightbulb is in series with the voltage sensor wire, which is allways hot normally, so it's switched off, and there is your clue in my first test there....
GENE