A tip for replacing an air conditioning compressor relay is to remove the compressor from the vehicle first. Most compressors can be serviced in the engine compartment, but it is better to remove them, states MDH Motors.
Another tip is to attach a clutch plate and a hub puller to the compressor after it has been removed from the engine compartment and its retainer has been removed.
When installing the replacement, ensure that all the frictional surfaces are free of dirt, oil and debris. Do not pound on the shaft during installation, as this can result in damage to the compressor. Instead, carefully press the hub into the shaft using a clutch plate and hub installation tool.
Any components not being replaced should be flushed with an A/C flush solvent, says You Fix Cars. After, they should be dried with filtered or shop air to ensure no debris remains.
After replacement, run a check with a high impedance multimeter, says AllPar. The voltage drop from the clutch to the battery's negative terminal must be low. About 700 is the maximum voltage that should read on the multimeter. Disconnecting the clutch and replacing it with an unpowered test light is a way to check voltage drops and find bad connections.