Component Functional Description And Diagnostic Overview - Radiator Cooling Fan Relay
WARNING: This page is about a different car, the 2020 Jeep Renegade. However, it is still accessible from the selected car via links, so may be relevant.
Functional Operation of the Radiator Cooling Fan Relay: Depending on the type of relay being used for the Radiator Cooling Fan, the approximate resistance of the relay coil should be:
- 72-98 Ohms for a mini relay (larger square relay).
- 94-114 Ohms for a micro relay (smaller rectangular relay).
- 160-225 Ohms for a Printed Circuit Board (PCB) relay.
NOTE:
The coil resistance of a relay or solenoid can vary based on factors like temperature or age of the component. Typically a 10% variance is allowed on a new component at room temperature. Therefore, do not always assume that a component that is measuring slightly outside of the tolerance given is faulty. A faulty component usually will be noticeably out of tolerance.
Diagnostic Overview: With the ignition on and the relay commanded off , battery voltage should be present at the Cooling Fan Relay Control circuit at the PDC output.
- No voltage present would indicate either an open in battery supply somewhere from the source, through the relay coil to the output of the Power Distribution Center (PDC) or the LSD control circuit is grounded and the relay is energized. To determine if the relay is stuck on measure the voltage on the Radiator Cooling Fan Relay Output circuit with the relay commanded off. If voltage is present at the output circuit, but not present at the control circuit, it would indicate the control circuit is being grounded. If no voltage is present at the output circuit it would indicate an issue in the supply circuit path.
- Voltage present would indicate that supply voltage is present. Back probing and jumping the control circuit to ground should cause the relay to close if the coil resistance is within specification and the proper battery voltage is being supplied. If the relay doesn't close it would indicate low voltage supply or high coil resistance in the relay. If the relay closes it would indicate an open in the control path.