Fan always operates when A/C compressor clutch is engaged. In addition, fan is turned on in accordance with coolant temperature. Coolant temperature sensor sends a message to PCM. PCM controls fan operation through the radiator fan relay. Fan should not operate during engine cranking. Fan should always operate when A/C clutch is engaged and engine is running. With A/C off or on models without A/C, fan will operate when vehicle speed exceeds 40 MPH and coolant temperature reaches 230 F (110 C). Fan will turn off when coolant temperature drops to 220 F (104 C). At speeds less than 40 MPH, fan will operate when coolant temperature reaches 210 F (99 C). Fan turns off when temperature drops to 200 F (93 C). TESTING COOLING FAN MOTOR Disconnect cooling fan motor harness connector. Observe correct polarity. Connect battery voltage to fan motor harness connector terminals. See Fig. 1 or Fig. 2 . If cooling fan motor fails to operate, replace fan motor.
NOTE: If fan motor is noticeably overheated, system voltage may be too high. Check charging system.
FAN RELAYS & PCM Caravan, Town & Country, & Voyager 1. Remove radiator fan relay. Radiator fan relay is located on left frame rail, near radiator. Turn ignition on. Check for voltage at Gray wire terminal of radiator fan relay. If battery voltage exists, go to next step. If battery voltage does not exist, check for open or shorted Gray wire. Repair wire as necessary and check system for proper operation. 2. Connect jumper wire between Gray wire and Dark Green wire terminals of radiator fan relay connector. If fan operates, go to next step. If fan does not operate, check for open or shorted Dark Green wire between radiator fan relay and fan motor connector. Repair as necessary and check system for proper operation. 3. Check for loose connections at fan motor and fan motor relay. If all connections are okay, check for DTCs. If PCM detects a problem with cooling fan, a radiator fan relay circuit DTC will be set.
CAUTION: Check cooling fan motor operation before checking fan relay and PCM. Ensure PCM is securely grounded. 4. If DTC indicates a problem with radiator fan relay circuit, turn ignition off. Disconnect PCM harness connector. Check resistance between fan relay connector terminal No. 2 (Light Green/Dark Blue wire) and ground. If resistance is less than 5 ohms, repair short to ground in Light Green/Dark Blue wire. If resistance is 5 ohms or greater, go to next step. 5. Check resistance between fan relay connector terminal No. 2 (Light Green/Dark Blue wire) and PCM connector terminal No. 73 (Light Green/Dark Blue wire). If resistance is greater than 5 ohms, repair open in Light Green/Dark Blue wire. If resistance is less than 5 ohms, replace PCM. After repair, retest system for proper operation.
Sunday, August 10th, 2008 AT 9:11 AM