If I'm not mistaken, it's not a kick down cable.

The auto's in the '89 are electronic controlled shifting.
The cable simply tells the the trans where the throttle position is so it knows how much line pressure to apply for shifting under load. You can actually take that cable off the throttle and lock it in to place so it can't move.
You'd just have some hard shifting at low rpm or soft shifting at high rpm (depending on where you lock it). It would still downshift as TCM told it too.

1995 Trooper LS auto 3.2 DOHC /w SOHC intake
1989 Trooper 2.6 auto
1989 I-Mark RS DOHC 1.6
1991 Stylus XS DOHC 1.8