94 f150 alternator problem
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94 f150 alternator problem
Alternator wasnt charging. Replaced it and it still wouldnt charge. Jumped green wire from alternator connector straight to battery positive and it started charging. Rode like that for a day and now it wont charge.
Is the green wire supposed to see a temporary 12v when started is turning just to excite the alternator? Or is the green wire supposed to be 12v with ignition on?
Is the green wire supposed to see a temporary 12v when started is turning just to excite the alternator? Or is the green wire supposed to be 12v with ignition on?
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I just did an instrument cluster swap right before the alternator trouble. I noticed earlier that the charge light was not illuminated. Could a bad or missing bulb cause it not to charge? Does the regulator require 3v to trigger the alternator on? By jumping straight to 12v i probably damaged the new regulator...?
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Im trting to wrap my head around this. With the light out, the alternator cant see voltage from the battery so it wont know when to charge.
If this 12v is required to make the alternator charge, how does the engine continue to run if battery is removed?
If this 12v is required to make the alternator charge, how does the engine continue to run if battery is removed?
Cargo Master
Joined: May 2001
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I think there is also a resistor in parallel with the light to cope with a burnt out bulb. Once the system is making voltage it can supply itself. Not recommended to operate an alternator this way but it will work.
Post Fiend
Joined: Apr 2002
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From: Waterloo, Iowa
I think they just need a tickle to get excited, and then it's self sustaining. The battery is just along for the ride, the alternator handles everything - lights, ignition, etc.
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Any ideas?
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Fleet Owner
Joined: Oct 2005
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From: Kentucky
The exciter voltage is always there with the key in the Start/Run position. Without it the alternator is turned off. This is normal operation.
What year cluster did you put in? Common issue when folks do this.
What year cluster did you put in? Common issue when folks do this.
Fleet Owner
Joined: Oct 2005
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From: Kentucky
If the OP runs a jumper directly from the battery it works. This is not a ground issue. It's a supply problem.
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I put in. 95 i believe because i didnt have a tach. What is the common problem? The battery light?
Fleet Owner
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From: Kentucky
1994 - 1995 clusters should be a plug-n-play (1996 F150/Bronco should work too). If you used a 1992-1993 then you would have the charge problem. Either verify the year cluster and/or go back and check the plugs on the back.
Fleet Owner
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From: Easton,Ks
If you put in a 1995 cluster then your truck is a 1993 or someone swapped the wires on the plugs to run a 1993 cluster without a tachometer because the one that came with the truck had a bad PSOM in it.
Now you need to swap the wires back.
1992-1993 C250:
1992-1993 C251:
1994-1995 C250:
1994-1995 C251:
/
Now you need to swap the wires back.
1992-1993 C250:
1992-1993 C251:
1994-1995 C250:
1994-1995 C251:
/
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Junior User
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If you put in a 1995 cluster then your truck is a 1993 or someone swapped the wires on the plugs to run a 1993 cluster without a tachometer because the one that came with the truck had a bad PSOM in it.
Now you need to swap the wires back.
1992-1993 C250:
1992-1993 C251:
1994-1995 C250:
1994-1995 C251:
/
Now you need to swap the wires back.
1992-1993 C250:
1992-1993 C251:
1994-1995 C250:
1994-1995 C251:
/Will this work? I found the single charge indicator wire on my 94 connector, but the 93 connector diagram shows two, and input and an output.