95 Accord, Vtec, Hadsys Compressor, 23 oz system capacity:

Here is a bit of background info. I'm not the original owner of this Accord, and the overall condition of this vehicle was bad. It needed lots of work. The air conditioning worked, but I never used it while I was restoring the vehicle. A few years ago, when I hooked up a set of pressure gages for a general check of the system, the high side hose had an opening on the crimp; refrigerant started shooting out. I disconnected the gage asap; there was some refrigerant loss; had no idea how much. I finally got it road-worthy and inspected Nov., 2009.

Then, I notice the AC is not defrosting the windows. Here is what I discover:

AC fuses are ok.

Compressor clutch does not activate/spin with the system turned on.

Jumped the pressure switch [under battery tray near receiver drier] but clutch does not spin.

Figure pressure is low from 134 loss.

Added some charge [slowly], waiting for the compressor to kick in [eventually two 14 oz. cans, thinking the system might have been lower than I anticipated] but the clutch did not engage. Now, the system has to be overcharged.

The low side port area does not get cold when adding refrigerant, aka "beer can affect."

The high side port area gets hot but I am able to hold onto the line without having to remove my hand.

Next, jump the fan relay. Clutch starts spinning. [dont think problem is the relay -- both fans always work].

Notice there is no cool air out the dash vents. Compressor does not cycle on and off, it just stays on.

There is no apparent ice buildup anywhere in the engine compartment [haven't looked in the dash area yet].

The pressure on the high side keeps climbing. I have to remove the jumper on the relay before the system reaches 450 psi.

The pressure on the low side starts normal and slowly goes to below 28 psi and stays there.

Both pressure gages confirm the compressors not cycling on and off.

There are bubbles in the sight glass, as if the system is low, even though I know the system is now overcharged.

I was not able to locate the AC Diode under the drivers side dash to check the condition or test it, but the few techs I spoke to do not think that is the problem.

I did not check to see if the thermostat connector is the issue. I will check this first and hook the gages back up to the system, and get back to this thread. I'm posting this now, because I doubt the thermostat connector is the problem. Of course, I'm going to have to vac out some of the 134 to get the charge at least close to correct. Other than that, I need to find out why the clutch does not spin, and why the compressor does not cycle on & off., so, if anyone has any thoughts on what the problem probably is, please let me know.

 

check for A/C Thermostat
The A/C thermostat is located on the evaporator housing. The A/C thermostat turns OFF the A/C compressor clutch if the temperature at the evaporator goes below 3°C (37°F) . This prevents condensation from freezing on the evaporator fins and blocking the air delivery into the passenger compartment. The blower motor will keep running when the sensor turns OFF the compressor.

also check when turn ac on does fan spin???

 

Well, it was about 65 degress today. Since it is above the approximate 37 degrees at the evaporator, I turned on the AC. The dash blower motor fan is the only one that activates. The condenser fan does not come on. Is it supposed to come on as soon as the ac is turned on? If yes, what are the symptoms if it does not activate? I see there is single red a wire coming out of the compressor going straight to a connector and then to the condenser fan motor.

... But when the engine gets warmer the condenser fan and the radiator fan both come on at the same time, and then both turn off at the same time. However, as you know this is not related to the AC but a normal operation of the engine cooling system.

 

hi, i have a 94 accord lx non-vtec with the hadsys compressor....i've noticed that it actually takes more than two cans (13oz cans) of R134a to actually cools.

just curious, what does the gauges need to be at on the low/high psi when the car is on and off?

i was told:
30~40psi low/ 250~300psi high when the car is running
50~60psi low @ 80f/ n/a psi high when car is off

 

Static pressure when system off should be ROUGHLY the same as air temp. 80f = 80psi ROUGHLY. I don't have my data siting in front of me and I "CRS". You "CAN" use pressures to charge a system. However, it is best to use an actual recovery machine to remove and evacuate the system and then charge with the appropriate amount. Easy. I like easy.

250-300psi running is high. Actual pressures will vary depending on humidity and air temperature.

 

To the OP; Does the A/C light illuminate when the system is commanded on?

The evaporator temperature sensor could be sending a false reading to the ECM essentially telling the ECM that they evaporator is too cold. This will prevent the ECM from turning on the compressor clutch.

When you jump the pressure switch connector and the system doesn't turn on, but does when you jump the relay, this tells you that the ECM doesn't want the system to activate.
I suspect a problem with either the command switch on the dash or it's circuit, or the evaporator temperature sensor in the evaporator box.

On a side note, you should always use an actual A/C machine to discharge and charge your system to avoid creating an over or under pressure problem. It's easier. I like easy.