I have a 2002 Honda Accord LX V4. My compressor clutch doesn’t turn off.
mice replaced the compressor thinking it was that at first. My high side pressure has been hitting 600 psi before it blows threw the relive valve
I’ve pulled the relay it shuts off I’ve changed the relay same problem.
ive pulled the fuse on the driver side panel 7.5amp
it turns off. I put it back in it turns back on with the ac switch off.
where should I look next could it be a pinched wire?

 

The AC switch cannot fail to the ON position.

POssible overcharged system or overheating locked variable compressor, higher compressor temps cause higher , high side pressures. Also increased ambient temps, but its Oct.

The fixed orifice tube could be clogged to cause a higher side, but that will not keep the compressor from shutting off.

Bring system back in a vacuum. Use appropriate ammount of refridgerant on recharge.

 

How could I check if the compressor is over heating what would cause that. I’ve went threw to compressor?
clutch bearing seems to be fine. It’s not locked up or anything.

 

Huh.

Anyways. Yeah inside there are multiple pistons linked on a plate. They are made to create variable displacement. The unit would be replaced.
Probably bring the system back into a vacuum with a recovery tank. Start over with the fill. Get some fresh compressor oil in there.

Is it a FOT or receiver drier system?

 

If the AC runs even with the AC switch off, there is a short somewhere in the circuit.

You mentioned pulling the driver's under-dash fuse 3 (7.5A) will turn it off. With the ignition in the ON position, that fuse supplies power the A/C compressor clutch relay coil, while the ECM/PCM supplies the ground to the relay coil. Only when the relay coil is energized with power and ground, does the relay contact closes to supply power to the compressor clutch.

That would indicate there is an issue on the ground side going to the relay; which could be due to:

• Shorted heater control panel
• Shorted ECM/PCM relay control
• Shorted wire

Locate the connector to the AC pressure switch and unplugged it. The AC pressure switch is in the circuit after the heater control panel; but, before the ECM/PCM. If the compressor doesn't run with A/C pressure switch disconnected, the short in the system is probably at the heater control panel or wiring before pressure switch. If the compressor still runs with the AC pressure switch disconnected, then the short is in the wiring after the pressure switch or at the ECM/PCM.

 

Does the switch provide a + or - 12v to the relay? Either way, a stated above something is causing the ON voltage to be present at the relay.

 

The relay was already replaced.

I was thinking pressure switch too. Still that wont cause it to continue to run-on forever(could be wrong here). Only shut off when the pressure is too low / or undercharge.


It is ground side switched.

Shorten the circuit, unplug the connector. If it runs its getting ground somewhere before that point. As stated. Look for the damaged section of wire.

Wasnt the compressor removed, or 'threwn' ? So i was coming up with purely mechanical failures to explain.

 

Which is why I suggested the voltage is always present to the relay - in this case ground. I assume if the relay is inserted while the car is running you'd hear a click. Since it turned off when the relay was pulled, something is sending ground to the relay. It does seem like there could be a damaged section of wire touching ground that connects to the relay. This is assuming the relay is the last and only component that provides power to the compressor.

Just a note, probably irrelevant - I noticed on my '99 if I select defrost he AC light (and I assume compressor) activates as they should. If I then switch to vent or floor, the AC light remains lit and I have to press it to manually turn it off. Other vehicles I've had would deactivate the compressor when switching to a different mode.

 

The switch works.

If it clicks on initial operation. If you can tell. That A/C pressure switch is working. Saying it has enough of a charge to operate without damage. A low pressue safety.

The relief valve is the high pressure safety. The A/C pressure switch is the low.

Yeah, look for the damaged wire,connector. Get out your DVOM. Ooopps, you are not the guy..

 

That's ok! - The OP will see your information. That's where you guys come in - knowledgeable about the entire air conditioning system. I can only offer electrical advice.

 

Refer to my initial reply. Power is always present at the relay coil with the ignition switch in the ON position. There is likely a short on the ground side, since the relay coil is most likely receiving ground when it shouldn't. When power (from driver's under-dash Fuse no. 3) and ground is present at the relay coil which energizes the coil, the relay contact closes (think of it like a draw bridge) to allow power from under-hood fuse no. 58 to the compressor clutch.

This is the circuit diagram for the AC compressor controls for manual AC. In my suggested test, if the heater control panel or wire before the pressure switch is improperly sending ground, pulling the connector for the pressure switch would remove the ground if it was present before the pressure switch. This would indicate a problem with the wiring before the pressure switch or with the heater control panel, which is before the pressure switch.

If it still ran with the pressure switch disconnected, then the problem is after the pressure switch.

 

It senses high and low, ok.

Why isn't it sensing high? That would a threwn a code I would think?

 

Great schematic, thanks for posting. Saving it for reference. It appears then pin 3 (relay coil) has a constant ground (-12v) via D11. Pin 4 always has +12v when the ignition is on.

 

Chall? Come back...I wanna solve this..

So you all say it senses high and low? Im thinking just low..

How can the sensor sense high pressure from the low side of the system? The sensor is placed on the low side. It has nothing to do with the high, it cannot see it from its current location.

Looks like it is only a single pole 2 position control. Either it has enough and closed, or not enough and open..