the truck is a 3.9 V6 and in good condition but for some reason it wont start in the cold pretty much anything below -7 C , it has no problem starting in warmer weather. iv replaced the starter and solinoid, replaced the wires and fuses. i dont know what else it could be

 

What exactly is it going?
Turning over but not quite "catching"? Not turning over at all? Turning over weakly?
Could be a weak battery.

 

no, it doesnt click from the starter and iv checked the battery and its reading 12 volts, could it be the N or P switch, or the relay switch

 

I'd swap the relay.
If that doesn't work, try starting in neutral, or jiggling the gear-shift around when in park or neutral. When I replaced my transmission, I initially had problems starting in Park. I had to really jam the gear-shift up for the switch to provide a good ground.
If that doesn't work, I'd get a multimeter, pull that relay, and start checking for power and grounds at the proper pins.

Because, if I think right, if it was just a bad/weak battery, you would at least get a "click" or it would try to turn over.