Coolant enters the engine at the water pump, where it gets pumped through the engine block and up through the head where the Thermostat is located, It then goes through the Thermostat and into the radiator where its cooled and goes right back into the water pump. Ok, thats the Basic.... at the thermostat housing there is a hole where water is constantly being pushed through, that water is fed through a hose and into the heater core with the heater on, or into the coolant reservoir with the heater off... from the heater core (heater on) it goes back into the water pump so the water can be recirculated throughout the engine. With the heater off the water just exits the coolant bottle and goes back to the water pump through the same hose. The Renix style cooling system is over complicated i think, but basically thats how it goes.
1989 2 Door CHEROKEE "Milo"
4.5 Inch Lift, Rebuilt Renix 4.0L, AX-15, Neon 703 Injectors, 29 Spline Chrysler 8.25, Advanced Adapters SYE, V8 ZJ Driveshaft, V8 ZJ Steering Upgrade, Warrior Products Steering Box Brace, JKS Adjustable Track bar, JK Control Arms, 32x11.50 BFG M/T KM2's, Ion Alloy 174 Rims, Bushwacker Flat flares, 52x60 Kargo Master Safari Roof Rack, JCR Stage 3 Rock Sliders, JKS Quicker Disconnects