Need Help Asap !

[coyote kid]

i had to replace my fuel pump in my 88 2.5 i also moved to a external tank in the bed instead of the one under it because it was rusting out anyway when i finished i had the fuel pump wired to a toggle switch just off my battery my real problem is that when i started it the truck ran fine  but for some reason the volt gauge only read 12 volts so i tried with my multi meter and sure enough 12 volts so i replaced my alternator with a brand new one and i am still having the same problem 

[coyote kid]

does the fuel pump and the charging circuit work together in any way?

[onlyinajeep726]

Maybe it's just me, but I fail to see any problem.  If the truck runs fine and the alternator is putting out 12V, then what's wrong?

[coyote kid]

i don't think its charging becuase if i unplug the positive terminal it kills the engine

[relyt120]

you should be getting something like 14v off the alternator if it is functioning correctly. Take that baby to an auto parts store and have em test it.

[neohic]

... so i replaced my alternator with a brand new one and i am still having the same problem 

 

Twice now I've replaced an alternator with an parts store unit and had it fail right out of the box.

[jimoshel]

Pulling the pos plug, from the alt, should not kill the engine. The resulting spark will kill the alt. Try running a wire direct from the bat + to the alt output wire. Now pull the plug. See what happens.