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'99 TL - Original Owner - 285K miles. A/C has always worked and never needed any service to date. It worked fine for about the last month (the only time I have used it this year) until about a week ago. Last week, I noticed that it worked fine when the car started and for about the first 10 minutes or so. The air out of the vents (using top vents only) then gets progressively less cold until it is barely cooling the air at all. I have tried using recycled air button and fresh air button and it does increase air output with recycled air button on (as it is supposed to) but it does not make it any cooler.
I first checked the heater coil valve near the firewall in the engine bay. It is working properly. I even disconnected the cable to the valve for the summer and closed the valve to prevent any hot radiator fluid from reaching the heater core. I also researched the Acurazine site here and verified that the Acura Heater Blower Motor Repair Harness 04321-S0K-A00 is not burned where it connects to the blower motor - blower motor also works fine at all output settings on the dial. I saw in one post that there is a resistor part near the blower motor and I have not removed it and don't know how to check it for proper operation. Any thoughts would be greatly appreciated as it is getting hot in the Heartland now!!!
check fuses in engine bay and in car.
try to trouble shoot the relays.. if there are two, try swapping the high a/c relay with the low a/c relay.
you're looking for the compressor clutch to engage.
if that passes test...
try putting a gauge on the low side port. if refrigerant is low, add refrigerant
Just went through this in Houston with '12 Kia.
I thought A/C systems were closed...but refrigerant can escape through seals and o-rings.
I was like...there's no way my fairly new Kia has low refrigerant...after checking relays and blower motor, hooked up gauge to low pressure side port and sure enough, refrigerant was low
Last edited by justnspace; 05-18-2018 at 11:58 AM.
Thanks justnspace. I should mention that I have verified that the A/C compressor clutch is engaging with the A/C on. Also, the two fans behind the radiator and A/C condenser both are working when the car is at operating temperature.
Agree. A/C systems are generally pretty tight but with age the orings allow some seepage, up to 1/2oz a year or more. Our systems hold 22oz so after 15 yrs you are looking at just under half the charge capacity theoretically.
I checked the Acura service manual and it does provide for a self-test of at least part of the A/C system. I did this and the results came up with no error codes, but I thought I would post these pictures to help others. I am going to take the car to O'Reilly. They said they have an A/C gauge that I can use in the parking lot to check the low pressure side of the system near the firewall. I know that the low side pressure reading can vary with temperature, but does anyone have the proper pressure range for me to know if the system is running low on R-134a refrigerant???
I poked around in the service manual a little more and found the following: "If the low-pressure does not reach more than 93.3 kPa (700 mm Hg, 27.6. Hg) in 15 minutes, there is probably a leak in the system. Partially charge the system, and check for leaks."
I will update you all on the pressure reading I get after taking it to O'Reilly and borrowing their gauge.
you can look up the temperature chart on the internet.
even the back of the bottles of R134 will have the chart. I used the "A/C Pro" brand. it came with a gauge with temperature readings.
as a bonus, A/C Pro brand said it had sealant and the correct oil for the compressor.
so, it should seal any potential leaks...and keep the compressor lubed
FYI, It is detrimental to the AC system if you don't turn on the AC compressor on a regular basis. The O-rings will shrink and/or dry up causing seepage of the freon and/or oil. Over time the O-rings will fail to seal causing a low freon and/or oil situation and cause all kinds of problems. Such as intermittent AC functions, compressor failure, leaks, etc.
Lots of people try to save gas by turning off the AC but that is a mistake. In the long run with the AC turn off will be problematic.
Tip
As preventive maintenance run the AC all year around to keep the O-rings and compressor lubricated. Just keep the climate control on Auto mode and the AC compressor will activate intermittently as needed.
Here is a photo of an A/C gauge and the pressure it is reading of 40 kPa (276 kPa on the gauge) with the compressor clutch engaged and the A/C compressor running. This is well above the 93.3 kPa listed in the Acura Service Manual in one of my posts above. By the way, I do run the A/C for about 10 - 15 minutes a month in the winter months to lubricate the A/C compressor.
The only other thing I noticed is that the compressor seems to cycle on and off about every 20 seconds or so. When it is on, the condensor/radiator fans are both on as the system dictates. Any thoughts on a part that would cause the A/C clutch to engage and disengage like this???
AC diagnosis doesn't work that way. You need to provide high, low- pressures, and ambient temperature? Along with description of symptoms, including any history of symptoms?
Without knowing what the high side pressure is doing its's almost impossible to troubleshoot the system. Did you add a can of refrigerant. If so, was there any change in how the system operates?
First, I need to correct a quote I took out of the Acura Service Manual for the '99 TL. The following quote in the manual relates to when the A/C system is hooked up to a machine at an Acura shop and during the evacuation of the system: "If the low-pressure does not reach more than 93.3 kPa (700 mm Hg, 27.6. Hg) in 15 minutes, there is probably a leak in the system. Partially charge the system, and check for leaks." Therefore, this is not the low pressure reading your are looking for during testing the low side while the compressor clutch is engaged. The manual does not provide either the running pressure for the high or low side.
I have not added refrigerant to date as the temperature dropped over the weekend (A/C not really needed), and I was still perplexed by the low side pressure reading. I agree with the other comments that A/C pressure readings are temperature dependent (a basic principle of thermodynamics). I also agree that it would be best practice to have a gauge set to measure the high and low pressure at the same time. I may look into the cost of this on ebay/amazon, although it seems like a tool that I won't be using enough to justify its purchase. Alternatively, I may just wait another day until it is in the 80's again and then add some of the Pro A/C 134a refrigerant/oil/stop leak and see if it works. When I had the system running a few days ago I laser temperature tested the vents and they were only cranking out 63 degree air with the A/C on max and recycle. I have seen some videos on YouTube (Chris Fix) were he added this exact product and got 43 degree air coming out the vents. I will keep you all posted.
Photo of Pressure Gauge Readings with compressor running
Ok - I did this a little backwards. I went ahead and put a 22 oz can of R134a (A/C Pro Brand) into the low side port with the A/C running to see if it would help (The gauge on the can was crap and read 15 psi the whole time). It did not help the A/C blow any cooler. I then took the car over to O'Reilly and they loaned me their A/C pressure gauge set. Here is a photo of the low side and high side pressure readings with the compressor running on full blast A/C. Prior to the test pulled both cabin air filters to get max flow. The A/C is still blowing cooler air, but the laser temp. gun is only reading about 55 - 60 degrees coming out of the vents with the system on recycled air (this does not significantly cool the car down at all). Checked the relays and they are all working. Any suggestions as to why the A/C is not operating properly given these pressure readings??? Outside temperature at time of test today was 85 degrees and sunny.
Considering you've already added 22oz of refrigerant and the system capacity is also 22oz(21.2oz-22.9oz), It's probably overcharged at this point so I wouldn't add any more.
If it were mine, I would evacuate the system, throw a vacuum on it for an hour and recharge(with dye) to spec and recheck pressure readings, look for leaks and go from there. It could be you have air in the system(easiest fix), a failing compressor, bad expansion valve, or a blockage in the system(usually caused by failing compressor sending debris).
Unless you want to pony up for a vacuum pump you might be best served biting the bullet and having a shop take a look at it
So I did so more research last night before dropping cash on some A/C service shop. I found this link that has a very good explanation of a car's entire air conditioning system: https://honda-tech.com/forums/tech-m...oesnt-2900177/
After reading this information, it came to me that my house A/C needs the outside unit (that houses the condenser fins around the outside of the unit) hosed down at least once or twice a year to work properly. Dirt, pollen, dust, etc. fill up the spaces between the heat dissipation fins on the condenser and do not allow proper airflow through the condenser, thus preventing the A/C from working properly. The most common symptom of a partially clogged condenser is that the A/C will work but the temperature out the ducts will not be cool enough.
So I got out the garden hose this morning with a good spray nozzle and spent about 5 minutes spraying down and through the entire TL's condenser. Lo and behold, that appears to have fixed the problem!!! The A/C was blowing 55° to 60° air out the vents before the hose down. Now it is blowing 35° to 40° air with holding 2500 RPM while sitting in the driveway and during a test drive - outside temperature 80°. So my advice if you have the same symptoms (A/C working, compressor engaging, vent air not cool enough) is to hose down your condenser first as this may be the problem.
Hey MikeND, I can attest to your condenser cleaning recommendation. Bought my car four years ago, at 196K. One issue, was A/C output temp, maximum 44 Deg. at the center vent, on recirculate, fan at lowest setting, new cabin filters, with a 90 Deg. ambient. All system pressures with-in spec. Had condenser professionally cleaned, $50.00. Result, out-put air temp, under the exact same conditions, went from 44 Deg. down to 33 Deg. Now, four years later, the A/C system, continues to put out 33-37 Deg.air, consistently, depending on the ambient! NOTE: One ritual, I follow, is to activate the A/C system, at least once or twice a week, during the winter months, to insure that all A/C components stay lubricated. That 11 Degree improvement may not seem like much, but it makes a big difference, in overall driving comfort!
For you guys talking about manually cycling the AC on in winter - Does the system not run the AC when it's cold? I assumed it cycled it always. Seems to me if you manually shut it off the windows fog up. Also the car seems to drip water from the AC system when I pull it into the garage in winter. Just assumptions on my part, anybody know for sure?
The AC compressor will cycle on and off when the climate control is set to Auto Mode or by turning the front defrost on. It appears that the compressor is off if the Auto Mode indicator lamp is off or Auto Mode is not on the LCD display.
The other way is to manually turn the AC off by pushing the AC off button.
Water dripping from the AC drain hose may or may not be an indication of the AC working because not all the water is always drained fully from the evaporator drip pan. However, it is an indication that your AC compressor was/is working at some point. Depending on the climate control setting.
And yes, when the condensation is being evaporated quickly from the interior of the car or no condensation present is a good indication that the AC compressor is cycling or working with the climate control to literally suck moisture out of the passenger cabin.
05-18-2018, 11:48 AM
