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DIY Get rid of AC clutch popping sound

15196 Views 26 Replies 14 Participants Last post by  Andy351
My Pilot being out of warranty, I had to solve the popping sound when AC clutch disengages, by myself. Didn't want to get into an already lost battle with the stealer, as I would have to open a case, claim some goodwill, and pay for most of the cost of replacing the AC clutch, compressor and coil.

The idea is to install a flyback diode in parallel of the AC clutch on the AC compressor. Because the pr*ck is out of reach, I decided to install it on its relay. I don't know how to insert pictures into the text, so I have juste attached them to the post. Here are the steps:

1- Buy a diode, the biggest you can find. Mine is a 400V, 4 amp rated.

2- Solder a wire on each end. The side with the line on the diode is where you connect to the relay pin. The other end goes to ground. This is IMPORTANT. Installing it the wrong way will short the 12V line going to the clutch and burn fuses. I used a red wire to connect to the relay, and green one for ground.

3- Heat shrink the diode and connections

4- Open the relay box under the hood, passenger side. You will find where the AC relay is located looking at the diagram on the cover. You will need to remove the relay, and the one next to it to get room to work.

5- Insert the end of the red wire into the relay socket. The pin that goes to the clutch is the one in the middle.

6- Put the relay back on, make sure your wire get squeezed into the socket with the right pin. Put the other relay back as well.

7- Now you need to find a place to ground the green wire. Be careful. The metal plates with screws in the relay box is NOT a ground. This provides 12V to the relays. Safest way is to go outside the box and install it on the body.

8- Remove paint with a sandpaper where you want to install your ground. I used a round connector and a self taping screw. This may not be the best screw to use, but it works. You can add grease on it to prevent corrosion.

9- Don't forget to put the relay cover back on.

Enjoy a silent ride, thanks to a 4$ fix.

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You are my hero! I've already had the dealership "fix" the popping once but it is back and my Touring only has one year of warranty left. Now I know there is hope for me once the warranty runs out. I thought I was going to have to buy a Costco size box of replacement relays to keep on hand. Please post follow ups in case anything changes, thanks.
 

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Interesting. I'm an electrical engineer and I'm surprised it wouldn't already have one. Even my old Saturn had one; it was a replaceable part in the fuse box that looked like a fuse with a diode symbol on it. Perhaps the existing one failed? Radio noise aside, not having a flyback diode would cause arcing at the relay contacts and shorten its life, so good fix!
 

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Discussion Starter · #4 ·
Interesting. I'm an electrical engineer and I'm surprised it wouldn't already have one. Even my old Saturn had one; it was a replaceable part in the fuse box that looked like a fuse with a diode symbol on it. Perhaps the existing one failed? Radio noise aside, not having a flyback diode would cause arcing at the relay contacts and shorten its life, so good fix!
I think the diode is built-in the AC coil itself, and fails over time. Theoretically, a diode should be located as close as possible to the coil so that makes sense. The diodes you see in your relay box are for relay coils, not AC clutch coil. New parts with new numbers have been issued recently for compressor, coil and clutch.

I have had my Pilot for 2 years and 38k miles before having this problem. Now, it's been a full week since the mod and I confirm it really works. I didn't even try to replace the relay, just went straight ahead with the permanent fix. Hope this DIY will help other piloteers, beacuse this problem is very annoying.
 

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Pfl: very nice walkthrough of the diode retrofit. From what I read on this issue in the past 2.5 years, your wiring is similar to what others have done for the exact same symptom on the Gen 2 Pilot and Acura TSX.

My servicing dealer replaced the clutch, coil, compressor, as well as relay #4 in August 2017. I noticed the PN revisions indicating there was a change just as you cited. So far the popping from the A/C has been eliminated.
 

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I would like to thank the OP (PilotForLife) for posting this fix. I did this on my wife's 2017 Pilot Touring back in December and it has been pop-free for over five months now!

I'd like to note that I found an unused threaded standoff in the engine compartment near the fuse box, and I found a matching machine screw in my tool bin, which allowed me to ground the wire without any drilling, making it fully reversible before I trade in the car.
 

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I have a 2016 EXL with 38K Miles. When I turn on or off AC, I hear a popping sound that was never there before this Spring. This is the same issue as in this thread, right? Is there a TSB on this issue? I hate going to the dealer without a TSB in hand.
 

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I have a 2016 EXL with 38K Miles. When I turn on or off AC, I hear a popping sound that was never there before this Spring. This is the same issue as in this thread, right? Is there a TSB on this issue? I hate going to the dealer without a TSB in hand.
Yes, that is the issue. More specifically, the popping occurs as the compressor cycles on and off, so it sounds like almost a random occurrence, up to a few times per minute depending on the weather, so it's not just when you manually turn on or off the A/C.

No, there is no TSB for this, at least one that permanently fixes it. If you read more about this on other threads (such as this one: popping/cracking noise from audio system or other sites via Google search) you'll see the same complaints across numerous Honda and Acura models for many, many years. The typical warranty fix (replacing the A/C relay, A/C clutch, and/or A/C coil) doesn't seem to permanently fix the problem, based on replies in those threads. This fix in this thread is a permanent solution. Don't waste your time asking the dealer for a warranty fix. They will either tell you they can't reproduce it, that they do no know of a fix, or attempt a fix such as above that doesn't work. (My dealer actually ordered ONE new tweeter, which was stupid since I told them it wasn't localized to a single speaker. I told them to forget it.)

I thought the popping sound was only on Touring and Elite models. Does this affect all trims?
Not sure if it's all trims, but there's definitely posts from EX-L owners reporting the issue.
 

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I would like to thank the OP (PilotForLife) for posting this fix, people like you are AMAZING!!! Our 2019 Elite started popping and doing weird stuff ( stereo rebooted and set time to 8:00, wouldn't shut off ) on the first warm day we had since purchase. A quick google search for 'honda pilot electrical popping stereo' brought me here.

I replaced the relay and installed this fix and the popping is gone and has been for a few days. Hoping this is a permanent fix. I used a 400v 3a diode. Totally not worth going to the dealership. I routed my ground wire through a tiny hold I drilled in the top side of the fuse box. Grounded to an existing ground below the fuse box.

Thanks again!
 

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Hi,

I'm having issues with our 2019 elite similar to what the previous poster (mike62282) reports, and also described in:

This Thread
This Thread
This Thread and
This Thread

The videos posted by users Claudio Di Gio and teacherpayne are exactly the symptoms my vehicle is presenting.

I want to get it to the dealer to document the problem, but I truly believe this is a software / integration problem, and I absolutely do NOT want my vehicle's interior stripped as the dealer throws parts at an issue they don't know how to fix. As I know from past experience and the poor pilot owners' stories in those threads above, it never goes back together the same and you live with rattles, clicks, and noises for the rest of the car's life.

Like I said, I truly believe this is a software issue, however in the 4th thread listed above, someone linked back to this thread as a potential fix. It sounds like it has application, however I have no evidence that this AC clutch issue is correlated to the issues I'm seeing - There are times I experience my issue when we have not been using AC/defrost and also, most tellingly, the crackling sounds from the speakers continue after the engine has been shut off and will continue until the door is opened.

Can the OP or some other expert chime in whether adding a snubber diode to this circuit is a valid fix for this seemingly separate issue?

Thanks!
 

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Update: it appears I was too soon to to praise the fix above, maybe, just not sure. Having a $50k vehicle with issues like this really is frustrating.

Earlier this week the popping / buzzing started again. I removed the diode fix described above and the weirdness continued, I could hear the buzzing from the speakers even with everything in the vehicle off, so I thought. It turns out the RES screen was locked up and not turning off, even when everything else in the vehicle was off. I did some digging and found the Backup fuse controls power to the RES, as well as a bunch of other important stuff ( the vehicle wouldn't start with this fuse pulled ). After pulling the fuse, waiting a few seconds, and replacing, the buzzing is gone. Hasn't come back yet, but I've avoided using the RES as a test to see if the buzzing comes back.

Fast forward to yesterday. Diode fix still removed, A/C starts blowing hot air, it blew the relay. Replaced the relay, cold air again.

I beginning to think both of these issues are probably separate, but manifest themselves with similar symptoms. Maybe it's all just related to buggy software.

Going to put the diode fix back in and see if I can keep an A/C relay for more than a week or 2.
 

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Hi,

I'm having issues with our 2019 elite similar to what the previous poster (mike62282) reports, and also described in:

This Thread
This Thread
This Thread and
This Thread

The videos posted by users Claudio Di Gio and teacherpayne are exactly the symptoms my vehicle is presenting.

I want to get it to the dealer to document the problem, but I truly believe this is a software / integration problem, and I absolutely do NOT want my vehicle's interior stripped as the dealer throws parts at an issue they don't know how to fix. As I know from past experience and the poor pilot owners' stories in those threads above, it never goes back together the same and you live with rattles, clicks, and noises for the rest of the car's life.

Like I said, I truly believe this is a software issue, however in the 4th thread listed above, someone linked back to this thread as a potential fix. It sounds like it has application, however I have no evidence that this AC clutch issue is correlated to the issues I'm seeing - There are times I experience my issue when we have not been using AC/defrost and also, most tellingly, the crackling sounds from the speakers continue after the engine has been shut off and will continue until the door is opened.

Can the OP or some other expert chime in whether adding a snubber diode to this circuit is a valid fix for this seemingly separate issue?

Thanks!
Update: it appears I was too soon to to praise the fix above, maybe, just not sure. Having a $50k vehicle with issues like this really is frustrating.

Earlier this week the popping / buzzing started again. I removed the diode fix described above and the weirdness continued, I could hear the buzzing from the speakers even with everything in the vehicle off, so I thought. It turns out the RES screen was locked up and not turning off, even when everything else in the vehicle was off. I did some digging and found the Backup fuse controls power to the RES, as well as a bunch of other important stuff ( the vehicle wouldn't start with this fuse pulled ). After pulling the fuse, waiting a few seconds, and replacing, the buzzing is gone. Hasn't come back yet, but I've avoided using the RES as a test to see if the buzzing comes back.

Fast forward to yesterday. Diode fix still removed, A/C starts blowing hot air, it blew the relay. Replaced the relay, cold air again.

I beginning to think both of these issues are probably separate, but manifest themselves with similar symptoms. Maybe it's all just related to buggy software.

Going to put the diode fix back in and see if I can keep an A/C relay for more than a week or 2.

There are DEFINITELY two different issues at play here.

To be clear:
  • If you experience random popping sounds in your speakers (a brief electrical snap sound), the diode fix posted by pilotforlife at the beginning of this forum thread WILL address it. Been working for me for 7+ months now.
  • If you experience popping sounds in your speakers when you lock/unlock the doors, it is caused by a similar relay feedback issue as above, but the diode hack documented by the OP will NOT fix that, but it presumably would if you added another diode grounded to the appropriate power lock relay.
  • If you are experiencing buzzing in your speakers (even with the car off) and other serious issues with your infotainment system on a 2019 Pilot (I.E., mid-cycle refresh) or newer -- as described by several of the links above by closetredbeck -- this is a NEW AND DIFFERENT issue and is NOT the subject of this thread.

The popping sound heard in the speakers is NOT an infotainment system issue and not a software problem. Is is an electrical feedback pulse induced through the speakers by the A/C and power lock relays, regardless of whether your infotainment system is on. If you have an infotainment issue, please post in one of those other related threads linked by closetredneck.
 

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There are DEFINITELY two different issues at play here.

To be clear:
  • If you are experiencing buzzing in your speakers (even with the car off) and other serious issues with your infotainment system on a 2019 Pilot (I.E., mid-cycle refresh) or newer -- as described by several of the links above by closetredbeck -- this is a NEW AND DIFFERENT issue and is NOT the subject of this thread.

The popping sound heard in the speakers is NOT an infotainment system issue and not a software problem. Is is an electrical feedback pulse induced through the speakers by the A/C and power lock relays, regardless of whether your infotainment system is on. If you have an infotainment issue, please post in one of those other related threads linked by closetredneck.
Just want to clarify: the issue I along with many other 2019 touring and elite owners are experiencing is not really a "buzzing" sound. It's more of a crackling sound and can be best described as a "digital audio skip" similar to what you would hear when a CD skips or your digital TV signal pixelates and the audio cuts out and comes back rapidly. I will try to get a sample of the noise.
 

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Just want to clarify: the issue I along with many other 2019 touring and elite owners are experiencing is not really a "buzzing" sound. It's more of a crackling sound and can be best described as a "digital audio skip" similar to what you would hear when a CD skips or your digital TV signal pixelates and the audio cuts out and comes back rapidly. I will try to get a sample of the noise.
That sounds a little bit like the helicopter noise the '16 pilot had before Honda came with a firmware audio fix. Check if you have neural sound enabled. If it is, disable it and see if it makes a difference.
 

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I just ordered a pair of 600V, 4A barrel diodes. I'm going to do as the OP described to get rid of the random popping from the AC relay. I'm curious if anyone did this same fix on the power door lock relay?
 
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