I have replaced the a/c compressor on my 95 cherokee 4.0. The clutch will not engage now. I know it is not the pressure switch. I have straight wired it to stay engaged for the short term, but need to find the cause of the problem. Also when the engine is under a load the air stops blowing through the vents and blows through the defrost? Any advise on these issues would be great. I live in atlanta and with the 110 heat indexes we have been having a/c is a must have. Thanks