PLEASE HELP ME FIGURE OUT WHATS WRONG WITH MY 77 FORD F250
 

I replaced the alternator in my truck about 2 months ago. the other day on the highway on my way to go 4wheelin when my truck started to sound funny at high RPM's and the radio kept turning off, my lights were also very dim. the problem got worse really fast, the truck would not rev up past idle after a while, unless it was being jumped by another vehicle. I concluded that it was the alternator, but i put one in and nothing changed. i also replaced the voltage regulator and still nothing. then i checked all the wiring and it was also fine. i was wondering if anyone would please help cause i really need my truck, especially in the middle of winter.

RE: PLEASE HELP ME FIGURE OUT WHATS WRONG WITH MY 77 FORD F250
 

Have the battery charged and tested. Looks like a very high drain but, that high would cause something to burn.
Get a voltmeter and a test light. Disconnect the alternator and regulator first. Make sure everthing is turned off in and out of the truck, ie. cab light, radio, head lights and even the hood light. Then connect one of the battery post to its cable, then connect the test light in between the other cable and its post. If there is a drain on the battery the light will come on. If the light comes on you can remove fuses and other electrical things one at a time until you find the draw on the battery. If the light is not on, connect the alternator and regulator one at a time and see if they cause the light to come on, if not you have no drain on the battery.
If its not a drain then its the battery not been charged, check the voltage on a newly charged and tested battery. Connect everything and start the truck, checking to voltage during start up and running. When the engine is running you should have about 14.3v. It would be better to test with a clamp-on DC current meter but they are expense. With one you could check the starter draw and the alternator output. Also does the truck have a meter in the instrumeter panel? GOOD LUCK

RE: PLEASE HELP ME FIGURE OUT WHATS WRONG WITH MY 77 FORD F250
 

check the ground strap from the motor to the frame, most likely on the back of the block