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partsman3 · 09-14-2011, 11:54 PM

Replace your pressure switch and see what happenes. Don't know how much you know about A/C systems. The 89 took R12. you said that you are using R134. If you are going by the label on the R12 system you may be over charged. When changing from R12 to R134 you only use 80% as much R134 as R12. Example 1 Lb is 16 oz, = 1lb of R12(16 oz) = 12.8 oz of R134. That could also cause your problem. The switch works off of pressure and R134 works at higher pressure than R12, thus not cycling making it freeze up.

There are still a lot of other things, but knowing what you are running (oriface) the switch is your most likely problem.

09-14-2011, 11:54 PM	#15
partsman3 Registered User Join Date: Aug 2011 Location: Argyle tx Posts: 36	Re: A/C work then Not...? Replace your pressure switch and see what happenes. Don't know how much you know about A/C systems. The 89 took R12. you said that you are using R134. If you are going by the label on the R12 system you may be over charged. When changing from R12 to R134 you only use 80% as much R134 as R12. Example 1 Lb is 16 oz, = 1lb of R12(16 oz) = 12.8 oz of R134. That could also cause your problem. The switch works off of pressure and R134 works at higher pressure than R12, thus not cycling making it freeze up. There are still a lot of other things, but knowing what you are running (oriface) the switch is your most likely problem.