97 gm pick up car door spring

I don't know what you are dealing with exactly, but in my business as a mechanic a simple piece piece of 1/2 water pipe, about 18" long served many purposes...perhaps leverage like an old water pipe will serve you as well.

Do you mean that little arm that keeps the door from opening too far? If it is, reach in with a piece of stiff wire and catch it. Bring it to the opening and catch it with needle nose pliers. Have the pin ready so you can secure it in it's mooring.

I used 3 zip ties and a vice. Worked like a charm.