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Alternator Light
#1
Don't claim to be an auto mechanic but I'll tackle anything and am capable. Stumped on this one though.
Started with a battery drain of two amps. Unplugged ALL fuses...one at a time. Still 2A drain. Unplugged voltage regular and drain stopped.
Replaced voltage regulator which fell apart when removed) and drain was fixed...but now alternator light was on when started. Since everything else in this car electrically was a mess when I purchased it, I went ahead and replaced the alternator. LIGHT STILL ON!
What's left? Starter solenoid and battery were also replaced while I was at it just to get new components under the hood.
I'm measuring 11.9vdc at alternator and battery. New battery...voltage regulator...starter solenoid and alternator. ALt light on when car started.
351C 4bbl.
HELP guys (& gals)!

Ted in Ohio
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#2
Does the light stay on after a few seconds? It is basically reading the difference between voltage at your ignition switch and at the alternator so it is possible that the line coming from the ignition switch to the dash cluster is faulty; it could be that the lamp is not picking up the voltage on the circuit card; the voltage going to the VR (green/red wire) is not correct.

When you start the car, what is the battery voltage while the engine is running? Is the VR doing its job? It should be 13.8 to 14.5 V with the engine running...a bit less if at idle speed but definitely should be above 11.9V!

Let me check your shorts!
http://midlifeharness.com

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#3
A new voltage regulator and alternator does not mean either, or both, are working properly. Especially the voltage regulator, been a lot of problems with them lately, especially the concours versions.



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
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#4
runninpony 
Don C;273128 Wrote:A new voltage regulator and alternator does not mean either, or both, are working properly. Especially the voltage regulator, been a lot of problems with them lately, especially the concours versions.

Ted in Ohio
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#5
Thanks. VR is the D2ZF Stamped Motorcraft out of CJPP. Alternator is from Advanced Auto Parts.

Had some time to put on it yesterday and found that battery voltage is the same with car on or off. 11.9VDC. Sad
Possible alternator cable...or...as you say-VR or alaternator

Ted in Ohio
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#6
those concourse VRs are total garbage. they are good for displaying a car that is never driven.

get a solid state electronic VR installed and then retest.

it is possible the bad VR damaged the alternator i had that happen once. you will have to switch parts to find the issue.

I had to do that on a friends car also.

he knew the car was running fine and i was showing him how to read the alternator tester tool and we found out his alternator was not charging.
we swapped alternators and still nothing worked.

so we bought a new electronic VR and installed it and tried to use his original alternator and again nothing.

it worked when i swapped in my extra known good alternator in combination with his new VR and then we also discovered a wiring error that caused a short which might of been the reason everything went wrong in the first place and it was done by the original owner before he even got the car.
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#7
Thank you...I'll give that a try. Will let you know what happens when I put the new, digital VR on.

Ted in Ohio
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#8
YEP! Bad "new" voltage regulator!
Thanks one and all!
Ted in Ohio

Thankyouyellow
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Ted in Ohio
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#9
That is a beautiful Vert!!!!

73 Grandé H Code. Headman long tube headers, T-5 Transmission, 3.70 Traclok, Lowered 1" all around, Aussie 2v heads w/ 2.19 intake, 1.71 exhaust, screw in studs, full roller cam 608/612 lift 280/281 duration LSA 112, Quick Fuel 750 CFM double pumper, AirGap intake.

- Jason


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#10
Wow that is one beautiful Vert 😎 Regards Lars

Sendt fra min E2303 med Tapatalk

So I'm a proud owner of one Mach 1 73! Regards Lars DK73whistling
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