Electrical 88 GT with 91 harness, no crank and low voltage on starter wire at ignition switch

Just got finished putting 95% of the car together and I went to test starter with fuel pump relay in to make sure everything was good and got nothing. Followed the no crank no start checklist and got the starter to work from touching the two large posts so I moved on and removed the connector off the small post and touch it to the post connected to the battery and the starter worked there too so I went inside the car and checked the white/purple wire at the switch and was only getting 4.7 volts while other terminals were getting 12.
My main issue is this is a wiring harness off of my old car that I put into this one and the previous person bypassed the clutch switch so I am not sure if maybe his hack job got messed up in the process of the install or if its something else but I am sorta at a lost currently as to why it is getting almost 1/3 the voltage it should be

Mustang5L5 said:

How much of the wiring harness is from a 1991?

Generally 1988 and 1991 are not compatible. They are wired very differently so need to know how much of the harness you are using.

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All the wiring in the car is from the 1991 car, there's no wiring left in the car from 1988

Mustang5L5 said:

Do you have 12v on the yellow wires?



The ignition switches on these cars are know. For not being so robust. Do you have a other one to try out?

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Thats the worst part I tracked it back to the switch after doing the tests so I did that first and tried two used switches so I cant imagine both are bad when I know that one used to work, my current idea is that it has to do something with the clutch switch since that white/pink wire is only getting 4.7 volts while other terminals on the ignition switch are getting 12, Im not entirely sure what is limiting the voltage but it has to be something in that circuit I believe and that would make sense why it is not starting from the key