1989 silverado A/C problem-wrong alternator?

[ellis479]

Hello,

I have a 1989 chevy silverado 4x4 with the 350 engine, auto. trans. My alternator started making a bearing noise so I replaced it with an AC delco 105A I bought on e-bay. I had a new compressor installed about four years ago, now since I replaced the alternator, the compressor acts like it does not want to disengage and makes a chattering noise while trying to make this transition. I noticed the parts stores have alternators for vehicles with A/C or without. Is there a possibility that I have the wrong alternator?? Thanks ellis479

[jyount]

The reason for the different alternators is different pullies, possibly the a/c would have more amperage. compare it to yours

[ellis479]

jyount,

Hello, the pulleys are the same. The alternator I replaced was 100A and the one I installed is a 105A both delco. What do you think would cause the AC compressor to not kick out like it should? It acts like it's holding back and makes a chattering sound till it finally disengages? This compressor is a delco, replaced all A/C parts four years ago. lost freon due to installer not tightening a connection. Had recharged, could loss of compressor oil be an issue? This unit has about 13,000 miles on it since I don't drive this vehicle except on weekends. Any ideas? Thanks ellis479

[brcidd]

This chattering is typical of a bad cycling switch (on accumulator) they did this in late 80's early 90's--switch can't decide to be on or off--- goes into rapid rapid contact closer- unplug switch and jumper connector to prove it..It is completely unrelated to your alternator....

[ellis479]

brcidd,

Hello, seems this just started right after I changed alternators, so I was just wondering if it was related to my a/c clutch not working right. Can I change this switch? If so where is it located, and what is the proper part identification for ordering this switch? thanks ellis479

[ellis479]

brcidd,

I just checked my trucks accumulator. The switch I'm seeing is the low pressure switch, which screws into the side of the accumulator. If this is the right switch, is it under pressure if I remove it to replace this part?? thanks ellis479

[brcidd]

the switch is made to unscrew with pressure in the system--- you will get a small pttttt when you take it off....no big deal--- ask your parts man for the compressor cycling switch-- or sometimes they call it the low pressure cycling switch...yes it is mounted to the big silver can-- has an o-ring in behind it....

[ellis479]

brcidd,

Thanks for your help, looks like a pretty simple operation. ellis479