2003 Civic LX A/C Compressor not working

[elliottdl]

Hi I am working on my parents 2003 Honda Civic LX. The A/C compressor is not working and my electrical knowledge is very limited. I only know what I learned in autobody school which wasn't much. Mainly it was just how to solder and some basics. Anyway How much voltage should be coming from the A/C Pressure Switch? Its only showing around 3 volts is that correct. Thanks for your help. I am sure I will have other questions but we will go with this for now.

[brcidd]

Number one mobile a/c failure mode is loss of refrigerant due to a leak-- does your system show 47 plus psi in it static condition (engine off)? - if so compressor should be commanded on by ECM. if compressor is still off and there is adequate system pressure then:

Always start at the a/c relay- jumper the socket that feeds the compressor- Does pump come on? If so problem is an a/c input, such as pressure transducer, or evaporator temp sensor.

If compressor does not come on with a/c relay jumpered, then problem is in compressor or wiring to it. Could be a simple as bad plug on compressor coil, or a burned out thermal fuse on face of compressor coil. Or a too wide of an air gap between pulley and clutch driver...

so do some preliminary testing and get back with us..

[somick]

Originally Posted by elliottdl

Hi I am working on my parents 2003 Honda Civic LX. The A/C compressor is not working and my electrical knowledge is very limited. I only know what I learned in autobody school which wasn't much. Mainly it was just how to solder and some basics. Anyway How much voltage should be coming from the A/C Pressure Switch? Its only showing around 3 volts is that correct. Thanks for your help. I am sure I will have other questions but we will go with this for now.

As far as I understand you do not have to measure voltage at the pressure switch. Only continuity. If the system does not have enough freon the switch should not have continuity. The most likely cause is your system is low on freon.

The readings you get on the switch might be a biased voltage from another side of the circuit.

Good luck,
Sam

[brcidd]

I'm going to say that an 03 Honda probably uses a pressure transducer (3-wire) on high side- where as you don't try to jumper the connector.. or do continuity on the terminals.. Is yours three terminal or two terminal-- And I'm going to venture there is no cycling switch in lieu of a temperature sensor mounted on evaporator face-- because it is probably a TXV system...