I just bought a 74 Highboy with a 390 in it. The truck is in awsome shape and has a few small things that keep it from running well. I am having a heck of a time with the charging system. I have replaced everything and it still won't keep a charge. Any idea where to start?

 

When you say "everything" do you include battery? A bad battery will go dead in a short time after being fully charged. Test or have your battery tested.

Have you put a volt meter on the battery while the truck is running? You should have somewhere around 13.5 to 14.5 volts. Much more and you will ruin your battery, much less and it won't charge properly.

If you are not getting the proper voltage have your regulator and alternator checked at a parts store.

If the above all test good, I would start looking for the cause of the battery drain. With the truck shut off, pull the negative battery cable, put the red lead of your volt meter on the neg cable, and the black lead on the neg battery terminal. You will some where around the voltage of the battery. Start pulling fuses untill the voltage goes away and you will have found the circuit of your problem. You can trace wires and troubleshoot from there.

 

Welcome to FTE. jimlj's post provides some good information for you. Can you be more specific about what you replaced?

 

Thanks guy's! I have replaced the Voltage regulator, Alternator, cables, starter soleniod. I haven't tried the voltage meter yet but will later today.

 

are you sure you have the wires on the alternator in the correct place? Maybe the previous owner hooked them back up wrong.

Look here:

http://www.fordfuelinjection.com/pub...ALT_wiring.gif

Ensure it's hooked up like that.

You really need to hook up a volt meter and see if it's charging.

In fact, go out and buy a new battery while you're at it, it's cheap insurance, and you'll know its good, and you can start from there.

 

Sorry it took so long to get back with you guys! Well, I believe I found the problem! Found a wiring nightmare under the dash and used the link alcan60283 posted and it worked! Its a great truck! Took it out behind the house and climbed some hills! Best part is the woman loves the truck and told me she liked the old smell! Gotta love that! Thanks for the helpful info.

 

The way your suggesting to hook up the multimeter above you should be measuring amps not volts, since your meter is hooked up in series with in one leg of the power circuit. Make sure you are setting your meter to the current measuring mode (amps) and always start your measurement at the highest amp setting if your meter does not auto adjust.

 

Trucks holding steady at 13.5 volts and the problem seems fixed! The good thing is I replaced everything electrical and the truck has a fresh 390 in it! Went for a long drive and climbed some hills near the house and the old tank performed flawless! This is my seventh Ford truck and four in the 73-79 series. I had a two 70's, a 72 , 73 , 76, 77 and now a 74! The reason I bought the truck was when I was a young kid, I used to walk to school every morning and would pass by a Highboy that sat out infront of a house. The guy who owned it would get up and start it to let it warm up to go to work! That truck sounded so sweet. This truck sounds just like that one did, thirty years ago!

 

Arizona Bigfoot - Welcome aboard FTE. It seems as though you've got a "70"s Ford Truck Bug". 1 "variant" is fatal and unlike poison ivy, you can NEVER get rid of it. ONLY large doses of Blue Oval make it bearable. Enjoy the ride & keep the wheels on the down side.