Circuit/System Testing
WARNING: This page is about a different car, the 2011 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, disconnect all of the KR20 cooling fan relays.
- Ignition ON, verify that a test lamp illuminates between ground and the relay coil ignition circuit terminal listed below:
- KR20C cooling fan low speed relay terminal 85
- KR20D cooling fan high speed relay terminal 85
- KR20E cooling fan speed control relay terminal 86
- If the test lamp does not illuminate, test the relay coil ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the relay coil ignition circuit fuse is open, test all components connected to the ignition circuit and replace as necessary.
- Connect the red lead of the DMM to a control circuit terminal listed below. Connect the black lead to ground. Set the DMM on the diode setting. The DMM should display OL.
- KR20C cooling fan low speed relay terminal 86
- KR20D cooling fan high speed relay terminal 86
- KR20E cooling fan speed control relay terminal 85
- If less than the specified range, test the appropriate relay coil control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
- Command the cooling fan relay ON and OFF with a scan tool. The DMM should transition from OL when commanded OFF to less than 1 V when commanded ON.
- If the circuit voltage does not correspond to the specified values, test the control circuit for an open/high resistance or for a short to voltage. If the circuit tests normal, replace the K20 ECM.
- If all circuits test normal, test or replace the appropriate KR20 relay.
NOTE:
The following test must be performed on all three fan relay circuits.
NOTE:
The following tests must be performed on all three fan relay circuits.
NOTE:
The following tests must be performed on all three fan relay circuits.