Have Honda Questions? Ask a Honda Repair Expert.
Hello my name is ***** ***** I will be assisting you with all of your vehicle questions today. Give me one moment while I review your question and come back with a answer. Please be aware I do not know your skill level or abilities so I will be asking a lot of questions and in a lot of cases we will respond to each other quite a lot before we find a solution. As far as phone calls are concerned that is the system prompting you, not me, and they do cost more money, I prefer text but in some cases a phone call is required.
what engine is in that car?
2.0 or 1.8
and is it a 2007 or 2008 civic?
1. Unplug the A/C compressor 3 pin connector and test the A/C thermal protector which is on the A/C compressor. Determine if the thermal protector is open; it should be a closed circuit and show continuity across the wires, if not, the thermal protector is bad. If a scan tool indicates A/C switch "ON" and A/C clutch "ON", then skip this test and look for a faulty A/C clutch relay or A/C clutch.2. Test the voltage on the BLU/WHT wire at the thermal protector to determine if it has a 12 volt reference, if not, check for an open wire between the under dash fuse box and the A/C compressor. If there is a reference voltage, backprobe and ground the wire with the engine running and the blower fan turned on and see if the compressor turns on. If the compressor turns on, this would indicate that the A/C request circuits to the Powertrain Control Module (PCM) are good and the problem would be with the A/C request ground signal provided by the from A/C control panel.3. The A/C control panel should apply a ground to the Red/Black wire at the thermal protector, when the A/C switch is turned on. If the control panel is not grounding the wire at the thermal protector, check for an open wire between the thermal protector and the A/C control panel. There may be a bad input to the control panel if the Red/Black wire tests good.4. If the compressor did not turn on in test #2, then check for power to the A/C compressor clutch and look for a faulty clutch or a faulty A/C clutch relay.
On this system, the A/C compressor request circuit is somewhat complicated. The A/C request signal is sent to the PCM via CAN communication from the instrument cluster. The instrument cluster receives an A/C request signal from the underdash fuse relay box multiplex control unit. The underdash fuse relay panel multiplex control unit receives its request signal from the A/C control panel but that signal has to pass through the thermal protector on the compressor. Hint: the A/C control panel will not give a compressor request signal when the blower motor is inoperative.