Engine Cooling problem
1994 Dodge Caravan 6 cyl Front Wheel Drive Automatic
I have recently rebuilt the Air Conditioning system on this van and it works great, however, when I run the Air it causes the engine to overheat. After checking everything out, all of the components seem to be working except the sensor that starts the fan. I have searched the radiator and what I can see of the engine and can't locate the sensor to replace it. Does someone know where I need to look? This is a 3.3L engine.
A/C Radiator Fan Control Switch Switch monitors compressor discharge pressure and signals A/C fan relay to cycle radiator fan when compressor discharge pressure exceeds parameters. Switch is mounted to high pressure line, near condenser connection block, on right side of radiator.
ELECTRIC COOLING FAN OPERATION 1. Electric cooling fan should not operate during engine cranking. During A/C operation, pressure transducer on A/C compressor discharge line delivers an input signal to Powertrain Control Module (PCM) to indicate A/C operation. The PCM will then turn on electric cooling fan. The PCM is located on fender in left front corner of engine compartment. See Fig. 1 . 2. If vehicle is not equipped with A/C or A/C is off, electric cooling fan should turn on or off as coolant temperature sensor determines coolant temperature and delivers input signal to PCM. 3. The PCM uses input signal from coolant temperature sensor for operating high speed and low speed fan relays for electric cooling fan operation. Fan relays are located on fender in left front corner of engine compartment. See Fig. 1 . 4. Electric cooling fan is controlled in different speeds in accordance with coolant temperature. See COOLING FAN OPERATING TEMPERATURES table.
Coolant temp sensor is next to the thermostat housing.