A/C not working - please advise

[RonJ]

Here's what fuse 14 protects:

Unplug the 2P connector to the A/C pressure switch and then, with the key in ON(II), measure voltage at the terminal in the connector for the Blu/Wht wire. Also test whether grounding that same wire terminal causes the fans to run and the compressor clutch to engage.

 

[yasen]

Here's what fuse 14 protects:

Unplug the 2P connector to the A/C pressure switch and then, with the key in ON(II), measure voltage at the terminal in the connector for the Blu/Wht wire. Also test whether grounding that same wire terminal causes the fans to run and the compressor clutch to engage.

Thank you for the detailed explanation on Fuse #14.
Pressure Switch: Just want to clarify, I need to measure voltage on pressure terminal itself (it has 2P prlug on the top), not on the harness connector which goes to pressure switch, right?
And next, ground the blue/wht wire from the harness switch which goes to pressure terminal and check for fans? To do the second step choud i push my AC button to ON position?
Thanks.
P.S. Sorry for so many clarification notes, I just want to make sure that I am doing everything you want me to do in a correct way, and I really appreciate your help.

 

[RonJ]

Both tests are done on the wire harness connector. No need to turn on A/C button for second test, just key in ON(II) or engine running.

 

[yasen]

Both tests are done on the wire harness connector. No need to turn on A/C button for second test, just key in ON(II) or engine running.

Good, I think we got it! I just did a test you wanted me to take. So, there is no DC voltade on Blue/White wire on the pressure terminal harness wire plug.....And as a result when I am connecting this wire using jumper cable to the "ground" - no changes at all.
Thanks

 

[yasen]

OK, I did more testing by searching for this problem and did found out something.
1. I did try out whatever described here http://www.ht-archive.com/showthread.php?p=42431858 in post number 2 and my thermal protector shows continuity. here is the same test on "accepted Answer" post: http://www.justanswer.com/questions/1rzd7-my-ac-compressor-is-not-turning-on-03-civic-blower-works ...so I do have continuity on this guy.
2. My second test was taken from here from "accepted anwer post"
http://www.justanswer.com/questions/19z68-i-have-a-2002-honda-civic-ex-with-an-a-c-problem-i-have
so, I did jump the red wire that comes from the pressure switch to thermal protector to ground....no luck.

3. I did unplug switch from harness/themal protector, started the car and did jump red wire from thermal protector sitch (on harness side) to ground....didn't work. I did trace where this red wire comes from ....it come from pressure switch. I did connect harness/thermal protector connectin back, did unplug pressure switch and did jump the same red wire from pressure switch to the ground......and it worked after I sateryed car and put a/c to ON, all started - compressor/fans...... I did measure a resistance on both pins of pressure switch connector and it is 1.
Thanks

 

[RonJ]

Unplug the condenser fan relay in the hood fuse box, start the engine, and then jump terminal 2 to terminal 1 in the hood fuse box socket with a jumper wire. Does the condenser fan run? Then jump terminal 3 to terminal 1 and check for the same result.

Do the same tests for the compressor clutch relay to see whether the clutch engages.

Post the results.

 

[yasen]

Unplug the condenser fan relay in the hood fuse box, start the engine, and then jump terminal 2 to terminal 1 in the hood fuse box socket with a jumper wire. Does the condenser fan run? Then jump terminal 3 to terminal 1 and check for the same result.

Do the same tests for the compressor clutch relay to see whether the clutch engages.

Post the results.

OK, here is what I got:
1. Test on Condenser Fan Relay:
- terminal 2/1 turns condenser fan ON;
- terminal 3/1 turns radiator fan ON;
2. Test on Compressor Clutch Relay:
- terminal 2/1 turns compressor clutch ON;
- terminal 3/1, no visible activity;

Thanks

 

[RonJ]

OK, here is what I got:
1. Test on Condenser Fan Relay:
- terminal 2/1 turns condenser fan ON;
- terminal 3/1 turns radiator fan ON;
2. Test on Compressor Clutch Relay:
- terminal 2/1 turns compressor clutch ON;
- terminal 3/1, no visible activity;

Thanks

Unplug the clutch relay and then turn the key to ON(II). Do you measure battery voltage at terminal 3 of the relay receptacle? How about terminal 2?

 

[yasen]

Unplug the clutch relay and then turn the key to ON(II). Do you measure battery voltage at terminal 3 of the relay receptacle? How about terminal 2?

You mean Compressor Clutch Relay? Sure, will measure voltage on terminal 2 and 3 wnd will let you know.
Thanks

 

[RonJ]

Next do the Mode 1 and 2 tests on the Multiplex Control System:

 

[RonJ]

You mean Compressor Clutch Relay? Sure, will measure voltage on terminal 2 and 3 wnd will let you know.
Thanks

Yes, but measure voltage from the relay receptacle in the hood fuse box rather than the relay itself.

 

[yasen]

Unplug the clutch relay and then turn the key to ON(II). Do you measure battery voltage at terminal 3 of the relay receptacle? How about terminal 2?

This test done:
On the Compressor Clutch Relay plug terminal 2 = 12V, terminal 3 = 0V.

And two stupid questions, for the next two Mode1&2 tests for Multiplex Control System, what the "special tool" is and where "multiplex inspection connector" located?
Thanks

 

[RonJ]

This test done:
On the Compressor Clutch Relay plug terminal 2 = 12V, terminal 3 = 0V.

If the key was in ON(II) when you did this test, then you have found an important problem. Terminal 3 should have battery voltage. From all the information you have provided so far, this particular problem is probably caused by a bad hood fuse box.

But if the lack of voltage at clutch relay terminal 3 were the only problem, then the condenser fan should run, suggesting that there is an additional problem in the A/C circuit. My guess for the second problem is the ECU or Multiplex Control System or the wire in between.

I'm pretty sure that you just need to install a jumper wire into the Multiplex Control Inspection Connector. It's a 2P dash fuse/relay box socket.

 

[yasen]

If the key was in ON(II) when you did this test, then you have found an important problem. Terminal 3 should have battery voltage. From all the information you have provided so far, this particular problem is probably caused by a bad hood fuse box.

But if the lack of voltage at clutch relay terminal 3 were the only problem, then the condenser fan should run, suggesting that there is an additional problem in the A/C circuit. My guess for the second problem is the ECU or Multiplex Control System or the wire in between.

I'm pretty sure that you just need to install a jumper wire into the Multiplex Control Inspection Connector. It's a 2P dash fuse/relay box socket.

Will run these two tests tomorrow. I just want to make sure that I am going to use the correct multiplex inspection connector for this test.
Here isa picture of my fuse box:
http://lh4.ggpht.com/_wLCc6cdE13M/TAXyx3NvEpI/AAAAAAAAKQE/yY-oDxH3y-8/s800/IMG00145-20100601-2211.jpg

and here is an official document, I assume I have to use a connector on the right from the yellow switch.

 

[RonJ]

Yes, based on your diagram, the inspection socket is the one immediately to the right of the socket where the yellow connector is inserted. To verify, check whether that socket has 2 pins (2P). If so, use a jumper wire to short those two pins for the mode tests.

In the meantime, check local junkyards for a replacement hood fuse box.

 

[yasen]

Yes, based on your diagram, the inspection socket is the one immediately to the right of the socket where the yellow connector is inserted. To verify, check whether that socket has 2 pins (2P). If so, use a jumper wire to short those two pins for the mode tests.

In the meantime, check local junkyards for a replacement hood fuse box.

Yes, it should be the one. BTW, I cannot find any diagram of fuse/relay box where I will be able to see where "J" connector is which is used in test with Method 1. There are lots of connectors, which one is "J" I have no idea. Thanks

 

[RonJ]

Yes, it should be the one. BTW, I cannot find any diagram of fuse/relay box where I will be able to see where "J" connector is which is used in test with Method 1. There are lots of connectors, which one is "J" I have no idea. Thanks

All diagrams I post in your thread come from the 02-03 Civic service manual downloadable at the Manuals link in my signature.

 

[yasen]

perfect, thanks a lot. Will rus this test today.

 

[yasen]

Next do the Mode 1 and 2 tests on the Multiplex Control System:

hi, I am done with Mode1/2 tests. The result of Mode1 test is totally fine, all passed and no extra light flashing. On Mode2 test I am getting light flash on all units which is good..... but not A/C , so it knows that there is an a/c issue. Thanks

 

[RonJ]

On Mode2 test I am getting light flash on all units which is good..... but not A/C , so it knows that there is an a/c issue. Thanks

Fix the lack of power at terminal 3 of the clutch relay and then rerun Mode Test 2. Again, scout your local junk yards for a replacement hood fuse box. You must fix the known problem before doing anymore troubleshooting.