Leak Test - Evaporator Core

One of the most difficult leaks to find is in the evaporator core. To leak test the core:
1. Turn the blower fan on HI" for 15 or more seconds than shut if "OFF."
2. Wait 10 minutes.
3. Remove the blower motor resistor. Refer to "Blower Motor Resistor Replacement." Service and Repair
4. Insert the leak detector probe into the resistor block trying to get as close to the evaporator as possible. If the detector goes to a solid alarm, a leak has been found.
5. If possible, with a flashlight visually inspect the core face for evidence of refrigerant oil