'94 Grand Caravan Heating Problem

If you are referring to the auxiliary heater in the rear, it wont cause a heater problem in the front by bypassing the rear heater core,It may cause the van to take longer to heat up then normal. In extreme cold weather you wont get as much heat output as fast either . You can check for a fault code 17 in the computers memory, that would indicate a stuck open thermostat which will give you low heater performance or there is a possibility that the blend air door is out of adjustment. If the temp feels the same going into the heater core as it does coming out then it may be a blend air door adjustment. Do a search on TSB 24-05-94 if it is the blend air door this will explain in more details Glenn Beasley Chrysler Tech