Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
I have a 2008 Honda CRV which I’m checking the inputs and outputs of AC, I was watching a video from scanner on Honda oddesy with bad clutch, I’m thinking I have a bad clutch on the compressor because I have done the same procedures he did. When I activate the AC clutch with the scan tool bidirectional, I don’t see the clutch trying to engage but I hear the relay click there is powers on both sides of relay load and control, at the AC compressor connector test light on ground the light turns on when AC activated with scan tool also on the relay control side both light comes on when activated on pcm driver side with light to positive . The ac compressor has a 3 pin plug with one being power which I have when on but not sure where the other two goes to, can someone help identify what these other two pins are for and how to test them? Also a wiring schematic would help if possible as I want to make sure the compressor clutch is the issue, I tapped on the clutch to try making it come on but doesn’t when on, hope everything I wrote makes sense and thanks in advance.
As you can hear the clutch clunk if you still suspect the clutch is faulty you are testing for a mechanical wear issue rather electrical.
The easiest test method would to be to put pressure gauge(s) on the system and look for any pressure change when the clutch is activated.
The most basic tools engine off test method would be to remove the drive belt and either use your scantool or a by-pass connection to activate the clutch and manually check the change in mechanical ressistance when you activate the clutch.
Another method I sometimes use is engine running do a by-pass test while looking at the calculated engine load on your scantool. You should see a couple of perenctage jump in engine load when the clutch is activated.
" We're trying to plug a hole in the universe, what are you doing ?. "
(Walter Bishop Fringe TV show)
The ac compressor has a 3 pin plug with one being power which I have when on but not sure where the other two goes to, can someone help identify what these other two pins are for and how to test them?
The other to wires are a thermal switch.
"Knowledge is a weapon. Arm yourself, well, before going to do battle."
"Understanding a question is half an answer." I have learned more by being wrong, than I have by being right.
Hello Andy or anyone, the system is empty, I’m trying to find out where a leak may be coming from but before that I’m doing the same test procedure Paul uses on a 2005 Honda Odessy video by testing all electrical, But my main thing is trying to make sure everything works along with air compressor or clutch. At this point I’m leaning towards a bad compressor but want to be sure before replacing it, there is power on the red white wire when I command the clutch with scan tool, there’s power on the relay and everything at relay test fine , it clicks when command the compressor on with scan tool.
On this diagram, it shows thermal protectors on these other two wires, how does these work and how do you test them? What should you see on these two wires (power ground or) ? Appreciate any help given from anyone.
Just reading off the diagram I think if the thermal switch is open, then the relay wouldn't click. If you have power feed at the compressor, check for good ground and coil integrity like any other solenoid.
Compressor gets too hot, it will open the switch and hvac won't let the relay control work, no power to compressor, i think...
I don't know how well this would work but try a compass and hold it near the compressor clutch and command the ac on/off.
A better test would be at the relay, i think, to check the ground and coil integrity, with relay removed check for ground on load side pin, purple wire.
An amp clamp around this wire if you can would be best and easiest test.
Another question I have is, with engine running or ignition on, when you turn Ac on button from inside vehicle with system empty, should you see power at the compressor wire or not? I did this and don’t see power but when I use scan tool bidirectional mode I do have power and all sides of relay works, the relay clicks, all fans work too, not sure what I should expect to see at the other two wires for thermal protector .
Please anyone help as I want to make sure I’m doing correctly and be able to troubleshoot it correctly
I will still need to find the leak as system was empty.
I see that you can command the clutch on with the scan tool, and that it doesn't engage. Plus, you have power at the three pin connector during the clutch command. That means the clutch is smoked. Compressor time.
As for the thermal switch - with the system full of compressed air, engine running, do the cooling fans come on when you hit the A/C button? If they do, the thermal switch is fine. Scan data from the PCM can also back this up. With the engine running and the A/C button on, the PIDs 'A/C SWITCH' and 'A/C CLUTCH' should show on. If they're shown as on, then the thermal switch is fine.
You can also back this up with some resistance testing. The thermal switch is normally closed, which means an ohm meter across the two switch pins should show good continuity.
Great info Tyler and appreciate it, both fans came on with system empty while engine ran at normal temp, but yes I had power at compressor power wire when commanded on. Also both sides of relay where working with their signals while commanded on as shown on Paul’s video with Honda oddesy. The only thing was I didn’t know how to test the black two wires on connector.
Don’t recall seeing the fans on when ac button on while engine running, will check when vehicle comes back on Saturday. Now if pids doesn’t show on with system full, what should you go after? I had my friend filled system up with his machine and clutch never engaged.
Lastly, do you have information on what it would take to remove expansion valve? Not sure if dash would need to be removed for that.
Thanks
Compressor time.