Leak Test - Evaporator Core

Because the evaporator core is contained in a closed module and is inaccessible to leak detectors, it is one of the most difficult parts of the air conditioning system to check for leaks. To leak-test the evaporator core:

1. Turn the blower motor on to high for 15 or more seconds then shut it off.
2. Wait 10 minutes.
3. Remove blower motor resistor. Refer to Blower Motor Resistor. Blower Motor Resistor
4. Insert the leak detector probe into the resistor opening. If the detector goes to a solid alarm, a leak has been found.