I have a 2000 S-10, vortec engine, with 150,000 on it. The a/c clutch engages on and off with the a/c switch off. Works fine with the a/c switch on b ut is quite annoying by turning on and off with the a/c off.Also, when I turn off the vent blower (no fan selected)I get hot air out of the heater ducts. Any help for these two problems please? Thanks in advance.