electrical issue.... Alternator

bobs84ttype

Active Member
Joined
Nov 24, 2006
I installed an after market inst. cluster. there is no volt light provision. I wired the volt light to a 12v ignition source so the alternator will charge.
Problem is the alternator is providing 12v on the ignition side of the start circuit after the key is turned off .
motor stays running when key is turned off. unplug two wire connector at the alternator and operation is normal.
Any thoughts would help Thanks
 
I installed an after market inst. cluster. there is no volt light provision. I wired the volt light to a 12v ignition source so the alternator will charge.
Any thoughts would help Thanks

Don't do that, there needs to be resistance in that circuit to the lamp input (L) of the alternator.

Connect the +12 volts to the F terminal.

RemoveBeforeFlight
 
I repaired it.......I went and spoke with local alternator/starter shop. I was given a pair of diodes to place in line so that the power would only travel in the direction. to the alternator and not back to start switch.
 
hey i have a 87 monte carlo aero coupe with a gn swap and i can't get my alternator to charge, can you guys just clarify for me that single brown field wire (L) should be a keyed 12v ? thats the how i have it now and its still not charging , BOBS84TTYPE can you tell me more about the diode fix or maybe RMVBFRFLIGHT can tell me how moving the power to the f terminal will help? thanks guys
 
While running get a wrench and see if the alternator case is magnatized no excitation not field no charge if not we need to get 12v to the field wire if it dont charge then could be avr/brushes/ rectifier etc.

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Iam not sure about the the case being magnetized but there is definitely 12v to the brown wire so if that's all it needs to work I guess I should have the alternator checked out again
 
How many miles on alt ?? After 120k brushes may be needed and slip rings cleaned

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Make sure its 120 amp most are 70 amp and almost all suck from the auto parts stores one in 3 -5 may be good I say return it and get one from napa I also think a Cadillac one will work if its re clocked but you need 120 amp

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Do not wire the brown wire directly to switched 12 volts, it will kill the regulator. To do it properly, you need to pull the terminal from the "L" terminal location and move it to the "F" location on the alternator connector. THEN you can wire it to switched 12 volts. Or, use the Field Fix kit and call it a day.
 
Ok so basically changing the switched power to terminal "f" will solve my problem , or I can leave it as is and use the field fix ?,
 
hey i have a 87 monte carlo aero coupe with a gn swap and i can't get my alternator to charge, can you guys just clarify for me that single brown field wire (L) should be a keyed 12v ? thats the how i have it now and its still not charging , BOBS84TTYPE can you tell me more about the diode fix or maybe RMVBFRFLIGHT can tell me how moving the power to the f terminal will help? thanks guys

May have killed the regulator. The F terminal has an internal resistor to limit the current. So can run +12 IGN power to it.

The L terminal requires an external resistance (the bulb).

RemoveBeforeFlight
 
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