I'm troubleshooting a new to me 2006. I'm used to being able to run the air-conditioner regardless of outside temperature but it seems like this system is more complexed.
Does anyone know if it depends on outside air temp? Max cold is the only time I can get cold air when the temp is about 70-75 outside.
Technically speaking all AC unit's are affected by outside temp. The refrigerant is condensed with an air exchanger and then expanded through a valve. As the fluid expands it cools (Joules- Thompson effect). The composition of the refrigerant, temperature, and therefore pressure, of the upstream fluid, and pressure in the cooling coil affect how cool the air temperature leaving the vents gets. At some point, if the air is hot enough, it won't condense the refrigerant, etc, etc
However... all of that mumbo jumbo ^^^ probably doesn't apply. You're probably low on refrigerant. Modern AC units are designed to operate at temperatures within the range of normal temps. Even global warming normal temps...
IIRC on ours max cooling is like 65F or so, so you would hope that you can get cooling even at low settings (although the A/C will likely cycle on and off a lot) at that outside temperature level. Although of course, it's the inside temp that matters mostly.
Not sure what the computer is working with parameters-wise, but checking on the refrigerant level is indeed probably the easiest thing to start with if you are concerned. Just peep at the little window and you may have most of your answer. Or better, put an A/C pressure gauge (all of $20 or so) on the (correct) A/C port and take it from there. Since it's possible/likely you may need to refill your system, if you do the latter, you may want to get a refill system including a gauge -$30 maybe).
That it works on Max and not on any other setting is indicative of a bad indoor temp sensor bulb reading. The system looks at indoor temp (as read by the sensor), compares that to the requested temp, and adjusts damper doors accordingly. By the driver's right knee there are some slots that let fresh air pass the sensor. On the back side of that panel there is a hose that draws air across the sensor. It often comes off. I'd check that first.
If it's blowing cold on Max the compressor side of the system is working fine. It's either on or off, not variable. The variation is by air mixing between heat and cold on the cabin side. I'm assuming you can hear the compressor click on other temp settings too, just not feel the cold?
Yes, I can feel the compressor kick on and off and upon feeling the line exiting the compressor it is very cold. I have removed the cabin air temperature sensor and cleaned it with compressed air and then reconnected it.
The line exiting the compressor should be hot not cold. Low pressure gas gets compressed and the compression heats it into a high pressure gas. High pressure gas condenses into high pressure liquid. Expansion valve allows the pressure to drop. The expanding liquid evaporates and cools as it does so. Rinse, wash, repeat. As a side note, you can see from the diagram why overfilling the system with freon does no good at all. Cooling capacity is based upon volumetric flow of the compressor and side of the heat exchangers.
I'm assuming you mean the line returning to the compressor from the evaporator. That still shouldn't be 'very cold'. Cool maybe. The only point in the system that should be 'very cold' is downstream of the expansion valve through the evaporator. Leaving the evap it should have picked up energy from the cabin and warmed back up into a low pressure gas.
Out of curiosity, does your rear air play nice or it it also only functioning on Max?
id check the ambient temp sensor, make sure it's hooked up and clean. My mom's 100 has same symptoms and I'm pretty sure it's temp sensor as I just repaired a system leak and it cools great on max but not on 65 setting.
Well I tested the cabin air sensor and the outside air sensor at the same temp and got almost exact resistance readings. Is there a possibility of an actuator only opening when on max cold?
