Thanks for your response
More descriptive -- OK let me try to clarify this further. The climate control works perfectly except for the fact that when trying to engage the air-conditioning mode, the air-conditioning compressor fails to engage. When either pushbutton for air-conditioning mode is selected, the compressor will turn on once I tap with my finger on the relay located in the engine compartment. This is the relay that supplies power to the air-conditioning compressor clutch. It is definitely not a defective relay or the wiring leading to the relay.
There is voltage present at the relay socket trying to engage the relay, however the relay is not getting enough current to actuate it. The voltage is about 12.6 to 12.7 V, although once again, the relay does not engage. This is what led me to believe that perhaps there is not enough current (amperage) available to trigger the relay, although this seems unlikely as the relays do not take very much current to trigger them.
Therefore, I am trying to determine the source of the voltage that is supposed to trigger the relay. If the “electronic switching unit for temperature control” supplies the voltage it may be switched via a solid-state circuit within that unit that may be crapping out. I do not know if the electronic switching unit tends to be a problem, like the pushbutton control units are. If the voltage is a direct connection made by a simple switch within the pushbutton control unit, then I am completely clueless as to how to proceed from this point forward.
And yes, I have done a fairly extensive search yet have not come up with any similar problem.
I appreciate your response, and hope that someone else out there may have either experienced the same problem, or may be able to point in the right direction.