1976 Ford Truck Electrical Problem?
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1976 Ford Truck Electrical Problem?
I have a truck that I just put a new motor in. Before I put the new motor in I never had any problems with the charging system. But afterwards I can't get the alternator to charge the battery. 
. Eventough I have replaced the alternator, voltage regulator, starter relay,and fusible link to the alternator. I had the battery checked and it is good.I have also re-checked all the grounds a billion times and they are connecting good.The only thing that I Know it could be is a wire burned clear but I can,t find it. 
. Anyone know what this may be or how I can find out Any help you can give will be greatly appreciated. 
. PLEASE! Before I shoot myself or the truck one. 
Senior User
Joined: Jan 2003
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From: Addison,Texas
Is the battery not charging, or is the battery draining when the engine is off?
To check for the latter, you disconnect the positive battery lead and hook up a test light between it and the battery post and turn everything off. If it glows, something is draining power. Then you pull fuses until the light goes out and that tells you which circuit is toasted.
If it just isn't charging enough, you check the battery voltage with the power off, then start the engine and run it at the high idle speed and check the voltage with nothing but the engine running. That should be 1 to 2 volts higher than the battery voltage. If it's way high and it stays high when you turn on the headlights and the blower, the alternator isn't grounded. If it's low, you disconnect the regulator. If it stays low, check the regulator to alternator harness for a short. If it's at battery voltage, swap the regulator back to the old one.
ash
['can't say beyond that.']
To check for the latter, you disconnect the positive battery lead and hook up a test light between it and the battery post and turn everything off. If it glows, something is draining power. Then you pull fuses until the light goes out and that tells you which circuit is toasted.
If it just isn't charging enough, you check the battery voltage with the power off, then start the engine and run it at the high idle speed and check the voltage with nothing but the engine running. That should be 1 to 2 volts higher than the battery voltage. If it's way high and it stays high when you turn on the headlights and the blower, the alternator isn't grounded. If it's low, you disconnect the regulator. If it stays low, check the regulator to alternator harness for a short. If it's at battery voltage, swap the regulator back to the old one.
ash
['can't say beyond that.']
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Thanks everyone for your help. But I got the problem fixed. I think it was a problem of not really a bad ground but not enough ground and a defective voltage regulator.I had the reg tested before I added two more ground wires one more to the frame and one directly to the alt case.At that time it was good but I guess between the time I got it tested and fixed the ground it must have burnt out. I added those grounds and then went and had the reg checked again and it was bad, got a new one, installed it, and hot damn its fixed.
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Joined: Sep 2001
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Re-check ALL of your grounds to be on the safe side. These trucks are OLD and all of the ground connections, as well as many power wire connections have deteriorated. Bad grounds can cause all sorts of gremlins...
