A/C freon pressure switch
 

Just yesterday my compressor clutchstopped engaging when A/C blower switch is engaged. Connected the leads going to the pressure switch and the compressor engaged, did not want to run it long enough to check the drier site gage for activity. I have some freon pressure on the high and low sides. Any way to check the switch without losing R-12 charge?

Have you put guages on to check pressures? If the system is charged you will be able to see if the switch is operating correctly by monitoring pressures and using an ohmmeter or testlight on the switch.

Good luck,

I doubt that the switch would be the problem. But then there is a first time for everything. There is a much greater chance that the R-12 has leaked out. When you by-pass the switch look at the sight glass on the dryer. If the system has anything in it, the glass will look white as the freon begins to circulate. If it remains mostly clear there isn't enough refrigerant left to keep the switch closed.
Regards,
Randy D.

With respect to Mr. Durance let me use a couple of different words that might help. The "white freon" he refers to is the frothing of the freon because of air in the system. A fully charged system is totally clear and looks as empty as it does full so if you can determine the level of freon in the sight glass that will help you confirm or discount this part of your diagnostics.

Good luck

Found the problem. Had an intermittant leak on both ends of the high pressure line and freon was almost completely depleted. Thanks for the help