Recently replaced wire harness and charge back wire on alt. Wife drove truck next day, all was good just some pulsing in the lights, all lights. Was told to ensure ground on voltage regulator, after doing so I started the truck and it just kept on cranking. I turned off and removed the key, sol running and cranking. I immediately went under the hood and pulled the s and I terminals from the solenoid. Cranking stopped but engine ran on, had to remove ground cable to turn the engine off. This happened 3 or 4 times and hasn't happened since. Lights still pulsing and charging is just under 14 volts, any ideas?

 

several things to check would be ignition switch and plug and harness to make sure it is working properly.
Then check the starter solenoid and alternator for proper wiring and function. Sometimes the solenoid will get stuck and need replacing.
I would recommend doing the 3G alternator swap to eliminate the voltage regulator and all the attached extra wiring.

 

Thanks for the ideas. checked switch and harness, all is good there. Re checked alt wiring all is good there no shorts good connections good ground. Could a bad regulator be the issue?

 

generally if the starter keeps turning after the key is released then the starter solenoid is bad if the switch checks out fine.

have you put a meter on the Alt and the battery to see if you are getting steady amps and volts out of the alternator all the way to the battery? It is possible especially with the newer chinese crap parts most stores stock now that the regulator is bad.

 

I have checked voltage it's steady at both battery and alt, just a little low as far as I can tell 13.9, also I have installed an aftermarket voltage meter, it's an ammeter in the instrument panel but never worked since I have had the truck, also voltage drops when I turn something on while driving lights wipers turns

 

the stock alternators for these trucks are horrible at keeping up with any kind of draw on the system. That is why the 3G swap is so popular. it is a very quick and simple upgrade for the electrical.

 

Well alt is new, regulator is new solid state not mechanical, battery is new.new ground straps, also went over the whole truck with a wire brush cleaning the heck out of all ground I can find and making them right, I just can't seem to get rid of this dang pulsing in the lights, even rolling down the highway. The volt meter in truck no longer drops voltage when I turn something on I.e. lights, radio, turn signal. All is good there, just the pulsing. Any ideas where to go from here would be greatly appreciated.

 

Is the alternator "new" or "rebuilt"? Ran into trouble with a friend's Subaru alternator. He replaced it several times before getting a good one. During research, I found that apparently there is no legal definition of "rebuilt". So a cleanup could be considered a "rebuild".

 

My suggestion is to eliminate the old alternator and regulator and upgrade to a 3G as mentioned. There are 2 levels of output. 130 amp HO alternator that is most popular, or a lesser 95 amp unit.

I put a 130 on mine because I wanted to. (Extra lights, stereo, trailer towing) but if you don't have that kinda stuff than I would recommend a 95 amp unit.

 

The alt is new and I made them take it out of the box and test it before I took it home and installed it, I'm up in the air about the 3g swap I wanted to keep the truck as original as possible. My wife's grandfather bought the truck new in 70, it was given to me as a wedding gift when we were married 3 years ago. I've spent a lot of time getting back to the way grandpa drove it, wouldn't even crank when I got her and it was sitting in a field in az for five years do the paint was oxidized really bad. I've buffed her 5 or 6 times just to get the color back

 

the 3G swap was the only thing that got mine to stop the pulsing of the lights.

 

can someone explain what the 3g swap is. i would like to do something like this with my truck but i dont know what all would be involved. it looks like my voltage regulator is tied into the electronic ignition. thanks

 

The 3g alternator is a newer model of ford built alternator that is internally regulated and a higher charge rate, more amps and 14+ volts. Worth the time if you are running any added electrical components like a large stereo or high powered head lights and if you don't care about originality, pretty simple there are diagrams posted in lots of threads in the forum here. If your not keen on wiring I would suggest doing some research before diving in.

 

ok thanks. ill try to look into it. i have a 460 so i will have to find something that will work for that.

 

There are a few different models orig the 3g you should be able to find one that fits