RADIATOR FAN CONTROL
Fan control is accomplished two ways. A pressure transducer on the air conditioning compressor discharge line sends a signal to the Powertrain Control Module (PCM) which will activate both fans if necessary. In addition to this control, the fan is turned on based on coolant temperature sensor output to the (PCM) The PCM switches the fans on through the fan relays. Refer to Wiring Diagrams Manual for circuit and diagnostics.
Switching through the (PCM) provides fan control for the following conditions.
•Regardless of coolant temperature the fan will not run during cranking until the engine starts.
•Fans will run in accordance with following operation charts.
RADIATOR FAN OPERATION - ALL ENGINES
Radiator Fan Control A/C Pressure
A/C Off Low High - -
Fan On: 110°C (230°F) 113°C (235°F) - -
Fan Off: 104°C (219°F *) 111°C (231°F) - -
- *109°C (228°F) @ Vehicle speed greater than 12.8 Kmh (8 mph)
A/C On Low High Low High
Fan On: 105°C (221°F) 110°C (230°F) 1,448 Kpa (210 psi) 1,717 Kpa (249 psi)
Fan Off: 102°C (216°F) 106°C (223°F) 1207 Kpa (175 psi) 1,579 Kpa (229 psi)
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1998 Concorde with 3.2. I had problems with starting when warm in the hot weather. I discovered that the low speed fans were not coming on when the engine reached operating temp as per the Haynes manual. High speed comes on when it exceeds 230deg. again as per "Haynes". High speed comes on with the air conditioner also. I ran the checks as per Haynes as best I could. I am reasonably certain the relays and fuses are ok but not completely sure of my testing of the sensors. Tomorrow when it is cool I'm going to make sure the cooling system is full and throw a coolant sensor and a new radiator cap at it. Any ideas?
