Started out that my ac wasn't working. One time it would one time it wouldn't. When it did work it blew cold so we tried to jump the pressure switch. Stupidly, we ran a power wire from the battery to the plug on the pressure switch. Since then I have had an electrical short somewhere I have replaced the under dash fuse box, the under hood fuse box, as well as the pcm. Now my ac won't work at all. When you turn on the switch the condenser fan nothing comes on. The two ground wires that come up from behind the engine that bolt on by the thermostat housing have a small power source to them which comes from the PCM. When I unplug the PCM it cuts the power from those ground wires. However both fans come on when the car gets up to temperature.

Any Ideas...........

 

You've probably blown out the HVAC control panel. The voltage at the pressure switch should go to near ground when the button is pressed. If it stays positive all the time, the control panel isn't working.

Next after you resolve that, the reason why it is only cold sometimes is probably the clutch gap.

 

I don't think I am getting any power. Question if my heater controls were the problem if I were to un plug them wouldn't the short go away? And what do you mean by the clutch gap? I was talking to a Honda tech and he told me to change the thermal protector he said that was a common problem with them. What do you think?

 

If you were to unplug the controls, the A/C would definitely not work.

Do the test I suggested. Also you should note whether the condenser fans start and stop when you turn the button on and off.

The controls work on negative logic, the control panel pulls the wire to ground when it wants the compressor to run, this passes through the pressure switch then to the MCU where it becomes a coded signal to the ECU; the ECU detects that and turns on the compressor and fan relays.

Clutch gap is the distance from the clutch plate to the pulley on the compressor. If it's too wide there may not be enough magnetic force to pull in the clutch every time.

If you have one wire leading to the compressor, the thermal protector is simply in series with the clutch coil. If there's two small wires and one big one, the thermal protector is in series with the pressure switch.

 

First off thankyou very much for you input it is very much appreciated. I know that when Turn the **** and press the a/c button it doesn't common at all and it use to. I am going check the things you suggested thanks again.

 

Yeah, you were right I replaced the heater controls and now it works. It was very deceiving, though because everything else worked fine off the heater control. As for the A/C it was just low. Thankyou very much!