aniskhan

Hi!

I am new to the forums. A couple of weeks ago I got a 2007 Honda Accord, V6, automatic, with 50k miles.

Everything has been working, until a couple of days ago when the A/C started blowing not-so-cold air (warmish). Hot air works, the vents work, recirculation, auto, etc. I checked the fuses, and found that the A/C compressor clutch fuse, No 12 (7.5A) in the under-hood fuse/relay box was blown. I replaced it, and everything was working again (cold air, etc.). A few hours later it blew again. I replaced it and looked at the compressor to see the clutch engage, and it worked perfectly. Every minute or so the clutch would engage and compressor would work. Then, an hour later with A/C on, and the same fuse blew again.

Based on what I've checked in this forum and the service manual, I've done these checks:

1) HVAC self diagnosis test does not give any errors.
2) A/C and Radiator fans are working and turn on OK.
3) Fuse No. 30 (7.5A) in under-dash box is OK.
4) Tested the A/C compressor clutch fuse relay, OK.
5) Measured voltage in the relay's socket #1/ground, 12V, OK.
6) Shorted #1 and #2 of the relay's socket, clutch clicks, OK.
7) Ignition witch ON (II), relay's socket #4/ground, 12V, OK.

Before going on with more tests, I wanted to know if anybody else here has had a similar issue and found the culprit. I really hope it's not a faulty a/c compressor clutch. Would appreciate any comments or suggestions!

Best,
Anis

tech8

For Fuse No. 12, there is only the compressor clutch relay, fuse box, wiring/connector, and compressor clutch.

Closely examine the wiring and the connector going to the compressor clutch. If you don't see anything wrong, disconnect the compressor clutch connector. Turn on the A/C (of course the A/C won't actually run; but, the compressor clutch relay should be energized to close the relay contact and allow power from Fuse No. 12 to go through the relay to the wiring for the compressor clutch). If the Fuse doesn't blow, it probably is the compressor clutch.

aniskhan

tech8, I will try that. The big issue is that the fuse doesn't blow immediately, the last time it took about an hour of driving with the A/C on... I will try what you are saying to see if something happens, hopefully it will blow!

Also, is a resistance of 4.9 ohms between terminal #2 of the clutch relay socket and ground normal? Should it be between 3.9 and 4.3 as per spec of the clutch coil or does the wiring increase the resistance a bit?

Thanks!

aniskhan

I tried what you said above. However, before I did that, I hooked an amp reader on fuse 12's circuit and it constantly read 2.8 amps while the clutch engaged. The car ran on Max A/C for 30 minutes while parked, and the amp reading didn't vary much. Then, I disconnected the amp reader and took the car for a spin. After about 15 minutes of driving, the fuse blew (warmish air starting coming from the a/c vents). So, this led me to believe that it only happens when the car is moving, which probably means that it happens when the engine compartment is very hot.

In any case, the next day I disconnected the compressor clutch connector plug. I went the rest of the day turning on and off the a/c while driving. In the afternoon I checked fuse 12, and it had blown. And that was the only blown fuse.

Does that mean that there's an issue in the wiring from the fuse box to the clutch connector? If so, the only wiring diagram I have is Fig 5 from HVAC 2 V6 section of the service manual.

Thanks for your help!

tech8

If under-hood Fuse No. 12 blew even with the compressor clutch disconnected, then it may be an issue with the compressor clutch relay, under-hood fuse box contacts, or the wiring to the compressor clutch connector. However, first check the the proper 7.5A fuse was used as under-dash Fuse No. 30 (this fuse provides power to energize the compressor clutch relay coil, which together with the ground signal from the ECM/PCM closes the relay contact to allow power from Fuse No. 12 through the relay to the compressor clutch).

aniskhan

Fuse 30 under-dash is OK and has always been good since my first post. I also tested the clutch relay again and it's functioning good (magnet and circuit closing)

Now I have to check the under-hood fuse box contacts and the wiring to the clutch connector? Which one is more likely the culprit?

tech8

For Fuse No. 30, I meant to just check it was a 7.5A fuse used and not higher.

There is another possibility that the relay may somehow have a short and causing the No. 12 fuse to blow. I would think the wiring to the compressor clutch as the least likely; but, you never know what it may turn out to be. Even trying to think up the most logical causes sometimes turn out to be due to something else quite different.

aniskhan

I was checking again everything while the engine was on and I noticed that the a/c fan was not coming on at all. I checked fuse 9 (20A) was blown! I couldn't believe it, fuse 12 and fuse 9 are blowing randomly...

So, I disconnected the a/c condenser fan plug and connected my voltimeter to test for continuity. To my surprise, it started beeping! Then, I pushed against the fan frame and it stopped! I looked at bit lower and noticed that both the a/c condenser fan cables and the a/c clutch cables all are bundled together and go into a tight area on the right side of the fans frame. I suspect that the heat together with some sharp edge of the frame might've cut into the cables. I am not sure yet, I have to wait for the bay to cool down before I look further. So, definitely there's a short happening on the a/c condenser fan cables.

For the sake of helping others, I've attached a picture where I tested for continuity. My fingers are on the fans frame and when I would pull towards the front of the car, continuity would stop.




a/c condenser fan short circuit

condensershort

So I was experiencing a similar issue with the 7.5 MG Clutch fuse blowing. I left the Condenser fan off and found that the 7.5 fuse would not blow -indicating a short in the condenser fan (like original poster). How did you fix this? Where was the short?

Thanks for the update ahead.

holmesnmanny

that normally would mean the fan itself is the issue, replacing the fan should fix it

tech8

This is not correct. The condenser fan is on a separate circuit than the compressor clutch. Condenser fan circuit is protected by under-hood Fuse No. 9 (20A), whereas the compressor clutch circuit is protected by under-hood Fuse No. 12 (7.5A).

The original poster found (see post #8), both his under-hood Fuse No. 9 and 12 were getting blown and had a short circuit. When he pushed against the fan frame it stopped. He looked a bit lower and noticed that both the a/c condenser fan cables and the a/c clutch cables all are bundled together and go into a tight area on the right side of the fans frame. He suspected that the heat together with some sharp edge of the frame might've cut into the cables. He identified a short happening on the a/c condenser fan cables.

holmesnmanny

oh i missed that it was the "clutch" fuse blowing