I've been advised to start pricing a new residential AC unit for a problem I'm experiencing. The compressor won't run when called for by the thermostat. The serviceman determined that the compressor relay contact was sticking open. When manually closed, the compressor started to run, but quickly shuts off when the contact opens (after about 3-5 seconds). It there a simple fix, or has it about had it? The unit is a Carrier, model 38EN024310.