limeybstrd

Thanks for your response mercman. I believe mine makes this snap noise when the AC switches off. If I press the off button the climate control I hear the pop snap noise everytime. If I turn the AC on using the Auto there is no noise. Just when I press off.
Not sure if it was on this forum but there was a member that posted pictures of how they fitted this diode. They tapped into the blue and red wire that leads to the ac compressor. They unplugged the lower harness near the lowest part of the passanger side fan.
I learned that the line side of the diode is where the postive is soldered to and the other side is connected to the ground. I believe the wire that I solder from the negative side of the diode will be the one that connects to the ground? The positive side of the diode will be tapped to the AC compressor blue and red wire?
Regarding fires, would it matter what amperage and voltage diode to use, would this affect the chances of a fire?
Thanks.

limeybstrd

The other thing I forgot to mention or should I say ask. What has exactly failed, is it the diode that has failed on our clutch that causes this?
I thought if the diode failed then the compressor wouldnt even work? Sorry about the basic questions.

mercman

The diode is only used to suppress the spike created by the clutch coil when the power is removed, let me explain.
When a current passes through a wire a magnetic field is produced, get a long piece of wire make, make a coil, energize it and you have an electromagnet. Remember science class when you wound the wire around the nail, connected a battery and picked up the paper clips, that’s how the AC clutch works, only with more wire and a stronger battery, the magnetic field pulls in a disk that connects the AC pump with the pulley.
Now, just as passing a current through a wire produces a magnetic field, moving a wire through a magnetic field produces a current. To make a current you can move the wire in the magnetic field or move the field passed the wire, it doesn’t matter as long as there is motion between the wire and the magnetic field you will get a current. This is how generators and alternators work. They convert motion to electricity.
Now back to the nail, what you didn’t observe in the science experiment was that when the battery was disconnected the magnetic field collapsed. When the field collapsed the magnet field actually passed through the coil of wire on the nail and produced a current. This current (called counter EMF), (EMF = Electro Motive Force) flows out of the wire opposite of the battery current that produced the magnetic field. The peak voltage of the CEMF is dependent on the time it takes for the field to collapse and the size of the coil and energy stored, I won’t bore you with the math but the size of the AC clutch coil is large and so is the stored energy so you get a big spike.
Since diodes only conduct current in on direction they are used to short out the CEMF (spike) from the coil when the battery is removed.

The clutch coil is working fine; it is the diode or connection to the diode that went bad so the spike is no longer being surpressed.

Jeff

limeybstrd

Thanks for the explanation. So am I right is saying that this spike travels back up the blue and red wire hence the need to place a diode on this?

If the diode I purchase is not rated correctly what is the worse case scenarios? Meaning would it just blow the diode and the pop carry on? I would like to goto Radio Shak and purchase a diode and a soldering iron to remedy this issue this weekend. Anything else needed perhaps? I was thinking heat shrink?

bullyx2

Throwing my .02 in. I had this snapping issue for years and thought it was something I would just always have to deal with. I picked up a diode from the shack and followed the insrtuctions here. Been 6 months now with zero snaps. The diode I used was part 226-1103 , IN4004. Cost around a buck for 2 of them.

Jottle

I completely agree that this is the fix, but the dealership techs have ZERO knowledge about how to process this as a warranty repair even when I explain to them exactly what is happening and how others fixed it. They know very little about electronics, and the snap is quiet enough that it's often hard to replicate. This is why I hate the dealership because even when problems are identified, they either have no idea how to fix them, or the botch the repair and break something else. It's almost easier jus to install your own diode than try to convince the dealership that something is wrong with your car in the first place.

feuss2

iTrader: (1)

Is there a diode in the clutch coil assembly that goes bad?

limeybstrd

I believe I fixed the problem. Used a 3 amp 400 volt diode. I grounded it on one of the ABS pump bolts.

Switched it on, pressed Auto and then OFF a few times no pops noticed anymore.
I just wondering how long the diode will last for?

limeybstrd

Drove to work today with AC on, no more pops.

Just need to make the install a bit tidier, looks wise.

I did use heat shrink wrap and solder iron for a good semi pro fit.

However, I really dont like a the red wire that goes all the way around the passanger side of the engine bay to the ground point on the ABS pump. I guess to make it blend in more it would be best to get some of that black plastic piping.

limeybstrd

Just an update and a question actually, perhaps Im just paranoid. I noticed that when I sit in my car now at lunch time the AC compressor kicks in more than before as it does this the fan comes on for 30 seconds then shuts off, then compressor engages then fan comes on and off for 30 second intervals?

Do you think this modification has caused this?

mercman

No, that would be impossible. What is likely going on is your AC is a little low on refrigerant, have it pressure tested and recharged if low.

Jeff

limeybstrd

Thanks Mercman, It never did this today though. Only difference was that the weather was hotter today in the lower 80's where as when it did do the above the temp was cooler.

Perhaps since it were warmer the fan just stayed on to keep engine cool and I didnt notice it? I am not familiar with AC system at all.

Jottle

Good question. Merc, do you happen to know? I wonder if someone could look up this part. If the dealership won't replace it under warranty (because they're often incompetent), it might be an easy DIY fix for the rest of us. I too don't really relish the idea of having a wire running all around my engine bay when this is clearly a malfunction on Acura's end. It's just almost impossible to convince the dealership techs to address this, let alone for them to come up with a fix. Is the clutch coil assembly cheap? Or what exact OEM part do you think we should be looking to replace? I don't have an electrical wiring diagram, only the helm's manual for my car.

Jottle

bump regarding my question above....Anyone?

Jottle

Anyone had this fixed at the dealership? I'm still under warranty, and I'm going to attempt to get my dealership to finally fix this in a month or so.

mercman

Jottle, got your PM, sorry for the late response I have been very sick for the past few weeks.
Typically AC clutch suppression diodes are built right into the field coil or mounted under the field coil connector. The field coil and connector on the TSX are separate assemblies so I don’t know where it would be. The field coil is about $70 but it is the labor that’s going to get ya. You will have a hard time convincing Honda to change a working coil under warrantee. You are going to have to push them to contact engineering about this so they can at least find out where the diode is and replace it. I don’t have my 06 anymore so I can’t check for you.

Jeff

Jottle

Thanks very much Jeff. Do you, or anyone else here on the forum have any recommendations for how to escalate this issue if the tech says this is somehow normal, which is definitely is not. Can honda corporate help?

Jottle

Bringing this thread back from the dead to report good news. I found a local Acura dealership that was able to finally RECOGNIZE that this issue is actually happening on my car, and they're trying to figure out how to fix it for me UNDER MY CPO WARRANTY! Here's the thing, and where I need your help if anyone is still watching this thread: They're doing an investigation with their "master mechanic" to figure out what part needs to be replaced or where the defective diode is located. Merc correctly identified that it's either built into the ac clutch field coil or mounted underneath the coil. Does anyone have any idea where the diode is located on the 06' TSX? Hopefully, the dealership techs will correctly identify it, but I'd like to give them as much help as possible so that they rip out as few parts as possible! Everyone on this thread has had to fix this DIY out of warranty. So hopefully we can identify the correct part # to replace. This should help others who come along in the future with this issue.

Jottle

Here's an update. Unfortunately, even with replacing the ac field coil, the noise is still there. My service manager confirmed with acura that the suppression diode is supposed to be in the field coil, but that did not fix it. It's strange because everyone else inserting a diode fixed the issue. So we're calling acura client relations to get the regional manager out here to figure out what the issue might be. I'm sure it's a failed diode, but these mechanics are not vehicle electricians. Hopefully, we can identify where the diode is or what other diodes have failed to cause this problem. I'll keep this thread open to report the resolution.

Jottle

Well, for anyone who is interested, I've finally got the problem fixed after 4 years of this crap. The issue was not the AC field coil diode at all. A tech at my dealership EASILY! identified the issue, which was a bad relay that was arking. We're talking about a $6.00 part replacement. Replacing the relay fixed the issue 100%. I'm glad this is over. For anyone else with this problem, you might find that replacing the same part fixes it.

The part number is: 39794-SDA-A03

Tech's notes: "found A/C clutch realy arking when A/C compressor clutch is cycled off. Removed and replaced.

AWESOME

Jottle

Sadly. I thought this was fixed for good for me. Unfortunately, the snapping noise is now returning once more. So either the relay has shorted out again on its own, or something else is causing the relay to short. It's not as bad as it was before, but every few AC cycles brings back the snapping noise. I'm out of warranty now. So I doubt my dealership will deal with me again. However, I'll post back if I finally nail down the source of this continuing frustration.

mercman

The relay contacts are arcing because the clutch coil diode is bad or missing. The primary job of the diode is to prevent switch contact arcing. Replacing the relay will not solve the problem.

Jeff

Jottle

Glad to see you're still following this thread Jeff. The dealership people really have no clue. However, I believe they did in fact replace the part with the clutch diode. Before they replaced the relay that temporarily fixed the problem, they contacted honda engineering to see where the diode was located on the A/C system. They then replaced some parts which they claimed honda told them contained the suppressive diode. The part number as listed on my receipt is "38924-RBA-006 COIL SET. SOLEN" Do you think they missed it and that this is the wrong part?

When they replaced the coil set, I still had the snapping (leading me to believe that they did not get the correct diode location). Then they replaced the relay which they saw was visibly arcing still. That fixed the issue for a few months, but now the snapping is returning. Any ideas?

cwinterrowd

Jeff, you've got me curious.. by adding the diode (posts #46 & #62) is this simply masking the fact that the relay contacts are arcing, or does this prevent the relay contacts from arcing?

Since I installed the diode two years ago, I haven't had any issues with snapping, but I'm curious if the relay is still arcing because of a failed OEM diode, should I anticipate it burning out the relay faster? I assume if the relay burns out, that just means I'm running without A/C until I can replace it and nothing else in the car would be affected? It may not matter now, in the middle of winter, but I'd really hate to lose my A/C on a long road trip in the middle of summer all because of a relay and a diode.

Jottle, you mentioned the $6 relay (39794-SDA-A03) fixed the issue for a short time, but then they replaced the $67 coil set solenoid (38924-RBA-006) which supposedly contained the diode but didn't seem to help the issue. I'm trying to determine if replacing both of these at the same time is necessary to eliminate the problem once and for all, or if there's something else we're missing?

mercman

When the AC is switched on the AC relay closes and current flows to the clutch coil. The current flow produces a strong magnetic field that pulls the AC clutch plates together starting the pump. When the AC relay opens the current flow to the coil is suddenly stopped and the magnetic field collapses rapidly. The collapsing magnetic field produces a very high voltage across the coil. The high voltage needs a path to ground which is supplied by the suppression diode. This works because the polarity of the voltage is opposite to that of the voltage used to energize the coil. Another way to look at it is the energy flowed into the coil and created a magnetic field; the energy going in was 12 volts and several amps of current. When the source is cut off the energy stored in the magnetic field flows back out in the form of high voltage and low current. The high voltage jumps the relay contacts to the positive side of the electrical system. This causes the pop and damages the relay contacts. The magnitude of the voltage produced depends on many factors but it is in the order of several hundred or thousand volts. To the high voltage the positive side of the battery is as good as ground.
If I had one to test I would pull off the connector at the clutch and remove the relay. I would then use a DVM to test for the diode in the harness and coil pack.

Jeff

Jottle

Thanks. Well I'm assuming, based on your response, that the diode just wasn't in the part numbers they replaced (referenced in my posts above). That, or I somehow have another diode that's failed in the system. I don't want to let the dealership just replace the arcing relay again, because that's just a useless band-aid fix which will just eventually fail again due to the high current damaging the relay contacts again. Do you think this situation is potentially dangerous? If so, I might be able to get acura to finally get to the bottom of this by consulting the regional manager for acura in my area.

Jottle

bump

mercman

It’s not really a safety issue just a nuisance not just from the snap but the endless relay failures. Without having a TSX to look at I have no way of telling if your car has a good diode or not. I know my 2006 did not have any measurable spike when the AC cycled. I checked this with test equipment so it is safe for me to say the 06s have a diode.
If you can see the relay arcing then bring it back and have them change it again, keep doing this until they fix the root cause of the problem.
Jeff

Jottle

They replaced the solenoid first (before the relay) and I still had the snapping. So then they replaced the relay...which fixed it only for a short time. So the solenoid set didn't really help at all, and the new relay they installed afterwards eventually failed like the original one. I'm taking my car in tomorrow to have them try once more to find the root cause of the failing relay somewhere down the A/C electrical chain. I'll update as soon as I've verified a fix for you all.

Jottle

Well here's the sad and stupid final update. The dealership got on the phone with Honda USA engineering. And the engineers told my dealership that the two parts that were replaced already (A/C solenoid with the suppressive diode and the A/C relay should have fixed the issue). They then recommended as the next reasonable troubleshooting step was to swap my stereo amp with a known working one. This is total horse crap as my amp is just fine (checked years ago when I was trying to isolate this snapping issue), and the problem is clearly located within the a/c electrical chain. So I'm not out of warranty, and my dealership can't just gift me an amp for $500. So I'm back at square one and am just going to have to personally install the in-line diode and be done with it like everyone else on this thread. Honda has really let me down as even THEY don't know why I'm still having the current surge after replacing the part in the AC system that has the diode in it. I also found another thread on a honda pilot forum where the owners are having the exact same issues but were never able to solve the main problem. Dealerships were advised by Honda to replace the A/C and fan relays, which of course started to fail again in about a month just like mine did. CLICK HERE . Sorry I couldn't be more help with this, but I am done with Acura cars as they can't even solve a simple electrical problem.

zzzzdoc

Jottle, were you and Mercman ever able to come up with a solution to the problem of the speaker pops? I recently purchased a 2004 TSX and your situation perfectly describes my problem. If there as anyone else out there with suggestions I would like to hear from you. It is an incredibly annoying problem making the audio system unusable.

Jottle

Still haven't ever been able to solve this problem without going with a self-installed diode. See my reply in your new thread. cwinterrowd, did you ever solve the snapping speaker issue?

bullyx2

I installed the diode fix with a 99 cent diode form Radio Shack and it fixed the issue. I did this a couple years ago I'd guess and have had no issues since.

Jottle, sorry, I see we exchanged some messages back in December and I never got you the info you asked for. I basically followed the instructions that were posted on the site. Was a quick fix. As I mentioned, I wrapped it all up pretty good under the hood so hard to see what I did. I'll try to see if I can get a photo or 2 though sometime soon.

mercman

This is a long thread and I’m sure I said this before,
You must install the diode in the correct direction. A diode is a one way device; it only allows current flow in one direction. The diode needs to be installed so that the positive wire on the AC coil is connected to the diode lead with the band. This way when the AC clutch in engaged, the diode will look like an open switch and all the current will flow to the clutch coil.

If you connect the diode backwards (the band on the ground side) all the current will flow thru the diode and it will burst into flames.
So the band side to the + side of the clutch connector and the un-banded side to ground.

Look for a diode with current rating of about 10 Amps and a PIV of a 1000Volts or more.

Jeff

cwinterrowd

Since installing the diode, I haven't had any problems with snapping sounds in any of the speakers.

I haven't removed the diode and done any further troubleshooting though.