gm altenators
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Elder User
Joined: Sep 2002
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From: McAlester, OK
gm altenators
I got this gm 97 amp altenator with the bat termanal on the back and then the two prong thing labeled 1 and 2 on the side. A guy at work mumbled something about one going to an ammeter to turn it on and the second to... well after all of his talking and confusion I translated as... The bigger wire goes to the voltometer and the smaller one to a light connected to the ignition to turn the altenator on.
I played with it and played with it and the only way to get the thing to charge is to tie them all together. I ran it like this and the thing wouldn't shut off and it would throw my starter in gear
Although I have no clue why the ignition would still have power with the switch off since the ingnition power lead is directly on the switch. 
Can anyone tell me what the 2 prongs on the side of a gm altenator would connect to or are used for? And how to go about setting one up without an ammeter?
Clayton
I played with it and played with it and the only way to get the thing to charge is to tie them all together. I ran it like this and the thing wouldn't shut off and it would throw my starter in gear
Although I have no clue why the ignition would still have power with the switch off since the ingnition power lead is directly on the switch. Can anyone tell me what the 2 prongs on the side of a gm altenator would connect to or are used for? And how to go about setting one up without an ammeter?
Clayton
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Joined: Feb 2003
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From: Western Shore of Virginia
gm altenators
Clay: You must open the circut between the two small spade terminals in order for the alternator not to pass current thru when the engine is shut down. All you have to do to get it to charge is excite both terminals upon inital start up. the large eye terminal is for Battery current,put your ammeter in series on that line.If you have a Voltmeter pick up any 12volt soarce on the ign.side of the circut.
Postmaster
Joined: Jan 2003
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From: Durham, NC
gm altenators
Originally posted by Jim VA.
Clay: You must open the circut between the two small spade terminals in order for the alternator not to pass current thru when the engine is shut down. All you have to do to get it to charge is excite both terminals upon inital start up. the large eye terminal is for Battery current,put your ammeter in series on that line.If you have a Voltmeter pick up any 12volt soarce on the ign.side of the circut.
Clay: You must open the circut between the two small spade terminals in order for the alternator not to pass current thru when the engine is shut down. All you have to do to get it to charge is excite both terminals upon inital start up. the large eye terminal is for Battery current,put your ammeter in series on that line.If you have a Voltmeter pick up any 12volt soarce on the ign.side of the circut.
will just measure the output current of the alternator, you will
never see a discharge current from the battery.
Elder User
Joined: Feb 2002
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From: Maryland
gm altenators
The large one on the back to a heavy bat sorce. Then the spaid term closest to the heavy term on the back should go to (run) on your ign switch. Then the other spaid is the ground for the light on the dash.
Lead Driver
Joined: Apr 2002
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From: Littleton, New Hampshire
gm altenators
Clayton.
We had a discussion recently on here about making one wire alternators out of three wire alternators. If I understood correctly, I think all you need to do is feed the #2 terminal with 12 volts from a source that is hot ONLY when the switch is in the "on" position. That should eliminate the problem with the engine continuing to run after the switch is turned off. I'm not sure you need anything on the #1 terminal...If I'm wrong, someone correct me because this is how I plan to wire mine up when the time comes.
We had a discussion recently on here about making one wire alternators out of three wire alternators. If I understood correctly, I think all you need to do is feed the #2 terminal with 12 volts from a source that is hot ONLY when the switch is in the "on" position. That should eliminate the problem with the engine continuing to run after the switch is turned off. I'm not sure you need anything on the #1 terminal...If I'm wrong, someone correct me because this is how I plan to wire mine up when the time comes.
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Elder User
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From: McAlester, OK
gm altenators
Well I finally decided to put in the other ignition switch since the other one went kaputt. I had them both connected together going to the ignition switch first and it worked. So then I tried them both one at a time and the engine died both times when I took the batterie cable off.
So I guess the way to go is to run them both to the ignition switch. Of course I felt the ignition switch to see if it was hot and it seemed a little, but as to if it was just the 100 degree weather or the fact that everything runs through the switch, I don't know.
Clayton
So I guess the way to go is to run them both to the ignition switch. Of course I felt the ignition switch to see if it was hot and it seemed a little, but as to if it was just the 100 degree weather or the fact that everything runs through the switch, I don't know.
Clayton
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From: chicopee us
gm altenators
Greatnorth,
Hooking the #2 to the ignition is supposed to stop the current draw through the alt so the battery doesn't go dead if the truck is parked for a long time. The truck will not run on if #2 is tied to a constant hot source. My truck is setup with #2 to a constant hot and it starts up and shuts down properly. I also do not see a problem with draining the battery when the truck is left to sit for months on end. I have nothing hooked up to the other terminal.
I don't think it is a good idea to hook them both to the ignition (and you shouldn't have to for it to work).
Hooking the #2 to the ignition is supposed to stop the current draw through the alt so the battery doesn't go dead if the truck is parked for a long time. The truck will not run on if #2 is tied to a constant hot source. My truck is setup with #2 to a constant hot and it starts up and shuts down properly. I also do not see a problem with draining the battery when the truck is left to sit for months on end. I have nothing hooked up to the other terminal.
I don't think it is a good idea to hook them both to the ignition (and you shouldn't have to for it to work).
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