I have a 1995 Ford F150 that will not start. I replaced the fuel pump assembly, fuel filter and new fuel line. For some reason the truck won't start. I saw somewhere that sometimes the black is positive and the red is negative. Doesn't is hold true for the truck I own??

 

There are very few times that red is considered negative, but you cannot always go by colors because you can get into trouble that way.
Would you care to share with us why you replaced the fuel pump ?
Always ask because we don't know if the reason was the fuel pump or some other possible reason. Many times a fuel pump gets replaced when that was not really the problem. Once we have some idea what is going on and what has been done it helps to make some kind of useful worthwhile suggestion(s). What do you think?

 

I replaced the fuel pump thinking that was the problem but after asking a neighbor mechanic of mine helped me identify the problem was a faulty injector.

 

Thank you for the update, glad you got it fixed.

 

The injector was the problem before my fuel pump issue. I still have the faulty injector but I want to fix the fuel pump issue first..

 

Do you have any means to determine which wires are which. Which gets momentary power at the fuel pump when the key is first turned on? That wire would usually get connected to the red wire.

 

If you connected the wires incorrectly it will cause the fuel pump fuse to blow. Check that fuse before going any further. It should be marked on the fuse panel.

If the fuse is OK, you can try this,
Looking at the Diagnostic plug, hold the plug so the 4 upside down T's are on the bottom.
If you connect a jumper wire from a good ground to the RIGHT Hand side cavity of the plug, then turn the key on . This energizes the fuel pump relay which sends power through the inertia switch and on down to the fuel pump. At this time you should hear the fuel pump run. Do you hear it running? Yes - no ?