Engine Fan Does Not Operate, But A/C Fan Operates

1. With engine coolant temperature above 221°F, engine cooling fan and A/C fan should both operate. If engine cooling fan operates at specified temperature, system is operating properly. If engine cooling fan does not operate at specified temperature, proceed to step 2.
2. Connect a jumper wire from temperature/pressure relay ground terminal (brown-black stripe) to a clean chassis ground. If engine fan operates, repair open in wire from temperature/pressure relay to ground. If engine fan does not operate, proceed to step 3.
3. Using a voltmeter, check for battery voltage at temperature/pressure relay coil terminal (red-yellow stripe wire). If no voltage is measured, check circuit. If voltage is measured, proceed to step 4.
4. Using a voltmeter, check for battery voltage at temperature/pressure relay battery terminal (buss bar with red-blue stripe wire). If no voltage is measured, repair open in wire from temperature/pressure switch relay terminal to temperature/pressure relay battery terminal. If voltage is measured, proceed to step 5.
5. Connect a jumper wire from the temperature/pressure relay ground terminal (brown-black stripe wire) to a clean chassis ground. Using a voltmeter, check for battery voltage at engine fan relay coil terminal (black-yellow and red stripe wire). If no voltage is measured, replace temperature/pressure relay. If voltage is measured, proceed to step 6.
6. Connect a jumper wire from temperature/pressure relay ground terminal (brown-black stripe wire) to a clean chassis ground. Using a voltmeter, check for battery voltage at engine fan relay coil terminal (black-yellow and red stripe wire). If voltage no. is measured, repair open in wire from temperature/pressure switch relay to engine fan relay. After completion of this repair, the engine cooling fan should operate properly.