Old Dude, new to site '91 D21 base. I know it is late in years made for this kind of thing. I did research and purchased optional my year wiper stalk unit (square lever, used), also have purchased New style unit (round style NOS). Studied diagrams, learned to follow them through diagram. No Amplifier found in my system. I purchased one with 3 sets of double connections (Sentra). Could not find loom, but did find one, like it but different colors (possible to splice in). Question: Do I have to install inside by steering above floor? If I do this, then I do not need to wire through, into motor area? 31 year old truck! maybe impossible at this late date! Please let me know, I'll quite then.