Carrier 42HVM109303 Service Manual page 55

Safety
Electricity power is still kept in capacitors even the power supply is shut off. Do not forget to discharge the electricity
power in capacitor.
Connect discharge resistance (approx.100Ω 40W) or soldering iron (plug) between +, - terminals of the electrolytic
capacitor on the contrary side of the outdoor PCB.
Note: The picture above is only for reference. The plug of your side may be different.
Main parts check
1.Temperature sensor checking
Disconnect the temperature sensor from PCB, measure the resistance value with a tester.
Temperature Sensors.
Room temp.(T1) sensor,
Indoor coil temp.(T2) sensor,
Electrolytic Capacitors
(HIGH VOLTAGE! CAUTION!)
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