96 ranger rpm needle jumps up and down when a/c is turn on

[bnrr]

My rpm needle jumps up and down like crazy whenever I turn on my a/c and could hear noise coming from the engine while on idle speed or driveing at 35 miles or more. after this incident my on switch works just at the high fan setting only. I am thinking of replaceing the on swithch, because just a thought that it might be the problem. but before I do I just wanted to get advice from anyone in the ranger station community to point me in the right direction befor I blow off any money on the wrong part and just regret it big time. I also have freinds tell me that it seems that the noise is coming from the blower. the a/c is still cold when in operations, but still makes a lot of noise. please help any advice would be greatly appreciated.

Thanks
96 XL 2.3OL ranger/ fan and owner

 

[rtg143]

If you only hear the noise when the compressor is engaged, your compressor is probably going out. As for the high only, if the blower only works on high, it's more than likely the blower resistor.

 

[disciplerocks]

Not sure about the noise, but the idle surging is either from the ecu not getting a chance to relearn after disconnecting the battery, or the IAC valve is bad.

 

[bnrr]

rtg143 and disciplerocks thank you for your responds to my post. I will run test on both the ecu, IAC valve and the blower resistor and keep you guys posted of the results.
Thanks