Radiator Cooling Fans
The ECM controls radiator cooling fan(s) based on vehicle speed, engine coolant temp. and A/C switch position. The following tables list correct cooling fan operation based on certain conditions. See A/C SWITCH ON or A/C SWITCH OFF tables. If cooling fan does not operate as specified, see RADIATOR (COOLING) FAN CONTROL TEST .
A/C SWITCH ON
| Engine Coolant Temp. °F (°C) | Cooling Fan Speed | Relay No. (Off Or On) |
|---|---|---|
| Less Than 203 (95) | Less Than 50 | High |
| Less Than 203 (95) | 50 Or More | Off |
| 203-212 (95-100) | Less Than 50 | High |
| 203-212 (95-100) | 50 Or More | Low |
| 212-221 (100-105) | All Speeds | High |
A/C SWITCH OFF
| Engine Coolant Temp. °F (°C) | Vehicle Speed MPH | Radiator Fan |
|---|---|---|
| Less Than 203 (95) | All Speeds | Off |
| 203-212 (95-100) | 11 Or Less | Off |
| 203-212 (95-100) | 12 Or More | Low |
| 212-221 (100-105) | 11 Or Less | Low |
| 212-221 (100-105) | 12 Or More | High |
| Greater Than 221 (105) | All Speeds | High |