The pictures below are from Dave Barton's website, 240turbo.com. Here's a link to the page where these products are found should you wish to purchase them from Dave. No doubt they are available elsewhere and the choice is yours but this is pretty straightforward and Dave has an excellent reputation. The guy at your local auto parts store may or may not know what he's talking about.
https://www.240turbo.com/blackvinyl.html#3poleEFI
Assume that the plug is reusable. Pull the rubber boot back off of the plug and push it back over the black tubing. That way it will be there when you need it later.
Look in the open end of the plug. It should look like the pic below except yours will still have the terminals in place.

You need to extract the terminals. I would pull them all, first taking note of which wire is which in relation to the plug because, as you no doubt know, it only fits one way and you don't want to reverse the two outer wires when you insert the terminals back into the plug. Why pull them all? In your place I would want to cut them to the same length and use new terminals for all three wires. Otherwise if you reuse the the two unbroken outer wires they are going to buckle.
Back the open end of the plug. You will see the three terminals. In one of the arms of that cross shaped recess there will be a tang that keeps the terminal in place. Into this you can insert a small flat bladed screwdriver or something similar to depress the tang and then you can pull the terminal out the other side of the plug.
Time for another pic. The terminal should look like this. You can see the tang.

If you use the link at the top of the page and scroll down to where the individual terminals are shown you will see a link to crimping instructions.
Inserting the terminals into the plug is just a matter of getting them properly oriented and in the correct space.
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'80 DL 2 door, '89 DL Wagon, '15 XC70 T6
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