1964 c10 starting issue

[rawraw67]

when attempting to start my truck from inside the cab I get nothing !! unless I run a remote from the battery to the starter,it will crank over.I have power in the cab at the ignition switch,on the pink and the red with the key on,in the crank position the purple is hot.but will not crank over.I installed a new engine harness and a coil thinking this was my problem.it didnt work.can it be in the alternator wire harness maybe? or the horn relay?
my underdash harness is good and intach.why does nothing happen when you turn the key.