Manual windows/locks to power?
 

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By 2003 Ford was using option specific wiring harnesses in Rangers so no it wouldn't be "plug and play"

In older years all vehicle makers used a Base wiring harness that included wiring for most options so adding an option was easier, at the factory or for a DIYer

Then margins got tighter so most started using base model wiring harness and a different full option harness
Power windows and locks were a pretty basic option but.......................fleet or base model Rangers were sold at lowest possible price to customers that just wanted a small pickup, NO FRILLS
These would have the most basic wiring harness possible to save costs

You can look at the fuse panels for power window and door lock fuses, the spaces will be there, but if there are no connections inside then wiring won't be there.

But you can DIY it using stock Ranger window setups and door locks, there is not alot of wiring involved if you don't want "auto down" and "auto up" features.
The systems are fairly self contain, just add 12volts

Here are wiring diagrams for older power windows and door locks
These do not need connection to GEM module which the 1995 and up wiring required
You can use newer motors and switches but follow the older system wiring diagrams

I included a 2002 power window diagram so you can see the difference
You can add 3rd party Keyless entry once you have the power door locks, pretty simple to install