A/C problem. thinking I need to add freon, bought R134a kit - hooked up guage to low pressure line (no can) start the engine, full AC and the pressure is maxed out (way over 80 psi), then drops some for a few seconds, but still over 80 psi. looks like aux. fans are not kickiing in either. hot air blows out, but seems like when moving/driving the AC gets cooler
Model: A4 Quatto
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About your vehicle.
Does the compressor kick on?
Which AC line did you attach the gauge to? (high side or low side)
yes, compressor kicks on - hence it gets cold when driving, and did connect to low pressure side as that's the only fitting the guage will attach
I normally like to check both pressures in any case. I would say that it sounds like the compressor is weak. With the both gauges attached, (if possible) you would more than likely see that the high side is very low, and the low side obviously is very high, ..What you can do to get an idea as to that is see if the low side does go down some when the engine is reved, (to abour 2K) for a minute or so. That is also why it would get cooler when driving..There are various tests for the compressor electrical if it were not to come on, but with high side pressure on the low side, experience is the best teacher..Thanks
cannot check high side. reving to 2k & holding has no different affect. aux fans do not kick on at all. someone said something about a 40 amp fuse under the dash, but cannot see that one. This is a turbo if that makes a difference?
Well, if the low side is that high, and it's NOT over charged then the compressor has to be very weak. If the high side were to get high enough, then the condenser fan would most likely come on...This control module switches the A/C clutch and thus the compressor on and off. It switches the coolant fans and calculates the pressure in the refrigerant circuit on vehicles with High Pressure Sensor G65 and Heating, air conditioning or Air conditioning....However, to have a more accurate diagnosis, you would want to know what the high side pressure is. ..
what control module?
the AC clutch sounds like it's kicking on & off 'regularly'
does a weak compressor mean replacing it?
Sorry, that's the fan control module. Yes, a weak compressor would have to be replaced.
ASE Master, 30+ years exp. imports and domestic, former shop owner
so is there a fuse to check for this fan control module? If so, where is it on this car?