[Krill]

My AC stopped working. I let an auto shop check it and they said the system is not leaking and has full pressure. They said it’s the engagement clutch not pulling. But they would not replace/repair the clutch and wanted to replace the whole compressor.

I measured the coil behind the clutch to be faulty (open circuit). The clutch also had worn off all clutch material. So I ordered a repair kit with new coil, pulley and clutch. Replaced the parts and I set the clutch gap to 0,3 mm but still the clutch does not engage.

If I energize the coil directliy with +12 volts it pulls. But I get no +12 volts on the feed cable 8n the harness. Can’t find any broken fuses or relays. Green light on climate dash lights up.

-10 C outside so I thought maybe the AC wouldn’t run when too cold, so I heated the ambient temp sensor to +15 C but still no voltage on the feed cable.

Running out of ideas...

Does anyone have a circuit diagram?

 

[Avisitor]

Would check all the fuses with a test light.
Ground the clip and probe the two test points on top of the fuse
One test point above each leg.
Both sides lights up and fuse is good
Only one side and fuse is blown
No light and no power to fuse

You can also put clip to battery positive
And probe the clutch wire for 12 volts
If the wire is open or at 12 volts then no light
If wire is shorted to ground then lights up
Recheck with clip at negative battery post
And probe the clutch wire

 

[ajchien]

Link to 2nd gen manual.

Honda CR-V 2002 - 2005 Shop Manual – PDF Download

The 2002 CR-V Shop Manual is divided into 23 sections. The first page of each section is marked with a black tab that lines up with its corresponding thumb

procarmanuals.com

 

[Krill]

Ok, just came in from some probing. Fuses are OK and have +12 V on both pins.
The relay socket for the condensor fan has +12 volt on control circuit and +12 volt on one side of the high current circuit. When bridging the high current side the fan starts.
The relay socket for the AC clutch coil has +12 volt on control circuit and +12 volt on one side of the high current circuit. When bridging the high current side the clutch pulls and the compressor turns.
Both relays tested OK.
None of these relays receive ground signal from the control unit to control circuit side hence they don't pull.
What are the start criterions for the AC. Guessing evaporator temp sensor, gas pressure sensor, maybe outside temp sensor.
Green light on AC dash comes on and does not flash/blink any codes.
Heater fan works on all levels, AC light turns off when setting the fan to off.

 

[Krill]

I found the ECC self diagnostic test in the manual. It starts with two blinks on the recirculation button as indicates self diagnostic cycle started. Then it turns on fan in a few different speeds and switch between recirculation and fresh it turns on the AC (button lights up). Then if it it finds any faults, it's supposed to blink either the recirculation button light or the ac button light a number of times depending on fault. But no fault code blinks so I guess it detects no faults?

Maybe I should just wait for the temperatures to rise above 0 C and check again. I can't find which sensors to "fool" to make the control module believe the temp is above the limit for AC to start (if such a function is included on the 2006 auto petrol 150 hp iVtec with ECC).

 

[Carbuff2]

I can't find which sensors to "fool" to make the control module believe the temp is above the limit for AC

On older cars, jumping the A/C Pressure Switch (in the diagram above) should turn on the compressor, if only for a short time. Of course, the most professional way to check this is to hook up A/C pressure gauge to the system.

That said, I like your troubleshooting so far. 💪

 

[Krill]

Ac pressure was checked at a AC shop to begin with. Full pressure, no leaks.

 

[ajchien]

On older cars, jumping the A/C Pressure Switch (in the diagram above) should turn on the compressor, if only for a short time. Of course, the most professional way to check this is to hook up A/C pressure gauge to the system.

That said, I like your troubleshooting so far. 💪

@Carbuff2 I see there are stickies in the gen1 and gen3 sections for the service manual. Is It possible to sticky that link In post #3 to get a gen2 manual easier for people to find? FWIW, I know folks on a different thread have advocated temporarily jumping the connector to the sensor to test “nearly the whole circuit”, but if you’re just wondering about the AC system pressure you can check for continuity of the terminals to see if the switch is in closed position (assuming your switch is working), it’s step #7 of the AC pressure switch circuit troubleshooting on page 21-43 of the manual.


@Krill If youre not up to figuring things out by the circuit diagram above, you can go to that service manual link in post #3, click HVAC, then click Air Conditioning, then go to page 21-40 through 21-44 as it will give you a step by step cookbook process to work through the compressor clutch circuit, the AC pressure switch circuit, and the evaporative sensor circuit. I usually read both the diagram and the step by step directions so I understand what I’m trying to do; still sometimes I’m stopped/delayed because I need to buy a tool that I don’t have. It looks like you have gone through and checked a lot of the compressor clutch circuit already. Please note Step #2 in the compressor clutch circuit says check the ECT sensor reading ... I wouldn’t skip those types of points as I suspect that is a subtle hint that says the ECM is using ECT data in its decision making, and the trouble shooting steps are just not telling us directly.

 

[Carbuff2]

I see there are stickies in the gen1 and gen3 sections for the service manual. Is It possible to sticky that link In post #3 to get a gen2 manual easier for people to find?

Done! Thanks.

 

[Krill]

Finally the temp outside went above 0. I pulled the connector off the ac pressure switch and jumper switched it and the clutch pulled and the rad and cond. fan came alive.

So either the car has a faulty switch or low pressure. The Ac shop I went to to start with said pressure was fine so in case they’re not a scam shop I guess it’s the switch. Either way the system has to be purged, the switch replaced, system vacuumed an refilled. So it’s a shop job now.

Can’t believe it had a worn clutch plate, a faulty coil and a bad pressure switch (and possibly low pressure). Guess the clutch plate was working, althoug worn but the coil failed. Then the pressure switch died after ac being not used for six months.

 

[Krill]

I spoke to the AC shop this morning and they said they may have purged the system when checking it for leaks. In that case it makes sense that it was just the clutch/coil that had failed and not a lot of other following faults. At least I hope so, in that case it's just a refill away from a working AC.

I scheduled a time with them on Friday and will post results here.