ok,with eng running checked Vs at single small wire,on connector.I unpluged it and it reads 11.28v checked at pos term of batter.its 11.87 V
Is it possable the connector on plug (small red wire) is not connected to the correct female spade term on alternator? there are 4 different ones 3 small and one large.?

 

You have one (red) wire on a 4 prong plug? Is that one connected to the L terminal?

 

cant see where it is connected it plugs into the female spade terms on alternator,and they are not marked.there are four,one big one and three smaller looks like it goes to the third spade on alternator counting from far right to left,facing alt from front.the big term is at far right and wire seems to plug into third from right.a small spade term.Hope this makes sense

 

I'd have to find a schematic to see which terminal is which. But you're saying there is just one wire on the plug?

 

yes one small wire.I have schematic,but not clear as to what term is what.it just shows that wire going into alt to I belive the regulator to swith alternator on.

 

hope this downloads for you.this is for 95 f body hope its same for 94
http://shbox.com/1/starter_charging_95.jpg

 

The PCM does not "Excite" the Alternator There is a solid state module in the Instrument Cluster that sends a resisted voltage through the small red wire to "Excite" the Alternator.


You having Voltage on the small red wire tells me the 470ohm resistor in the Module is not burnt out.


With the engine off, The Regulator in the Alternator grounds the small red wire, Check for a Ground, If not present.....Bad Alternator Or the terminal in the regulator plug is stretched out & not making contact.

 

Thanks for reply,I saw that solid state in the wire diagram.wondered how that worked.Ok ,so when you say the alternator regulator grounds the small red wire do you mean when ign is turned off that term L on regulator grounds internally.? and if so I should be able to check the L term with plug off and it should be grounded??Or does it ground at the solid state behind dash.I tried pluging in a wire to plug and connecting it to L term of alt to make sure its connected and it still is not charging battery.I am so stumped at this point.

 

Thanks for reply,I saw that solid state in the wire diagram.wondered how that worked.Ok ,so when you say the alternator regulator grounds the small red wire do you mean when ign is turned off that term L on regulator grounds internally.? and if so I should be able to check the L term with plug off and it should be grounded??Or does it ground at the solid state behind dash.I tried pluging in a wire to plug and connecting it to L term of alt to make sure its connected and it still is not charging battery.I am so stumped at this point.

 

ok went out did some checks with my ohm meter.Alt body has good ground.small red wire disconnected from alt only has ohms only on diode setting .502 with ohm metter set on 200 ohms the only term on alt where plug goes (there's four) looking at alt from front of it.the second term from right.(next to bigger spade term) has ohms the other three dont.unless I set meter on 200k or above.ofcourse on diode they all have some resistence.the red wire when pluged into alt,connects to the third term from the right.Im just wondering if this is the L term on alt.?