if it's 86 or older it will have a single electric motor and a big orange transmission and that style is more trouble than it's worth. It's virtually guaranteed to break the brittle original housing. Gbodyparts has a new unit that's a new molded housing and refurb'd guts but it's a couple hundred bucks. IMO don't use that style.
Now, if it has three separate motors, that's the style you (and everyone else) wants. There's a 2 wire harness that plugs into a bulkhead under the dash and just runs under the carpet. Should be able to grab an OE harness from about any metric chassis car or be easy enough to build your own.