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The regulator you are referring to is the A/C thermostat. The two wires coming out of it operate the clutch on the A/C compressor, and the copper tube (filled with gas) is placed in the air stream immedietly down stream of the evaporator. The thermostat tube senses the temperature of the air coming out of the evaporator which causes the gas in the tube to change pressure (expand and contract) which opens and closes a set of contacts inside the silver box.
The problem with what you have done permanently joining those two wires together, is that the compressor will now run continuosly which if everything else in the system is working properly (your fridgey seems to think it is) will cause the evaporator to freeze up. Running the compressor in this condition will damage the compressor.
Some thermostats have an adjusting screw on them allowing you to adjust the cut in/cut out point, this allows you to set them to cut out to about 1 degree (at the evaporator) which usually equates to 4 or 5 degrees at the vent. That's about the coldest you can run the A/C without causing freezing. Unfortunately not all thermostats are adjustable. Have a look at your thermostat to see if there is an adjustment screw as it sounds like your A/C is freezing up. If it is adjstable don't touch it just yet. Let me know and I'll run you through how to set it properly. The pic below shows an adjustable thermostat, the adjuster on yours may not be as obvious as shown here.
To replace the thermostat in most cases requires removal of the evaporator housing which is why your fridgey has told you the gas will need to be recovered. He is also correct telling you that pre 1994 vehicles were filled with R12 refrigerant (no good for the ozone layer apparently) which needs to be replaced with the more ozone friendly R134a. It's not a straight swap though, R134a is not compatible with the oil or O-rings used in R12 systems so they all need to be replaced. The filter dryer also needs to be replaced. Then the whole system needs to be evacuated down to remove all moisture from the system before it can be regassed. All this explains the high price on his quote.
Tony
Last edited by YNOT; 23rd January 2011 at 07:22 AM.
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