The heater core probably failed and they bypassed it. It will not work without those two hoses going into the heater core.
89 GT Hatch: Custom M90 Supercharged w/ Ported Trickflow Trackheat Heads, Stage 1 cam, Streetheat lower / Sheet metal upper, Tweecer RT & PLX Wideband, 75mm TB, 1.6 Roller rockers, 3.73s, MSD 6a, Canton 7qt Pan+ Windage tray, 36LB Injectors, 200 amp Alternator, 75mm Pro-Mas MAF, 190lph fuel pump,Spec Stage 1 Clutch,SouthSide LCA's, Pro 5.0 Shifter, Steeda CC Plates / Springs, FMS Aluminum Driveshaft, New T5 w/ 2.95 first gear, Underdrive pullies, Zirgo 3300Cfm Elec. Fan, AFCO alum. radiator