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Discussion Starter #1
I live in Central New Jersey and my AC is blowing warm air at the vents even at the lowest temp setting. The AC compressor clutch is not engaging even when both the AC and the radiator fan are turning on. I checked the 7.5 fuse in the relay box and the 10A fuse in the interior fuse box. I replaced the AC compressor clutch relay because it was rattling but the clutch is still not engaging. The only thing left to test is the connection between the relay and the clutch. I haven't done that because it's very difficult to access the compressor connector. I disregard the pressure sensing switch and the refrigerant pressure because the compressor fan is turning on and off just like the compressor should.

So, it looks like I have a broken ac compressor clutch or coil. I have 3 options.

Option 1: Some shops I went to have quoted $900-$1100 to replace the whole compressor because they don't replace the clutch or coil only.

Option 2: Another mechanic quoted me with $400 labor to replace the compressor and refill the system with freon. I have to buy the compressor and all the miscellaneous washers and gaskets. No warranty is given

Option 3: Do the work myself. I will be buying a re-manufactured compressor. I have done smaller jobs like spark plug replacement, oil changes and serpentine bell replacement but never this more complicated job. I have the service manual that I can use to follow the steps for the replacement.

My biggest concern is dealing with the freon gases and refilling the system. I don't have the tools to recover the refrigerant. I don't a vacuum or the manifold to refill the system. I don't know anywhere where I can go and recover and refill the freon after finishing the installation. I don't want to contaminate anything that might make things worse in the future. Does anyone know anywhere I can go to do this in my area?

I need held here. What do you guys recommend?
 

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Option 2 is your best bet..

Otherwise do Option 3, Greenpeace will be mad but you will save money.
 

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Before you spend the money on a compressor replacement, it would be smart to do a direct test of the clutch.

Refer to photo below. It is my CRV, but your MDX will be similar.




The black wire that runs from the grey connector at the bottom of the photo, then between the two Freon pipe connectors is the power wire to the clutch. It's grey connector attaches to another wire that goes to the relay. This connection is usually clipped to the passenger side radiator support flange, with both wires running parallel to the side of the radiator. You are correct that it is a pain to access and disconnect for testing, but it will have to be done if you replace the compressor anyway. It is usually easiest to access by pulling down the plastic splash pan below the radiator. Again, this has to be done anyway. The best way to confirm a bad clutch is to run a jumper wire directly from the battery positive terminal to the clutch wire. If it actuates the clutch, trace the power flow back to the relay. If it still doesn't engage the clutch, proceed with replacing the compressor.
 

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Spend the money on parts and have the mechanic do it!

OEM Denso Condenser with element: $80 rockauto
OEM Denso Compressor: $290 rockauto plus shipping
OEM Denso Expansion Valve: $17 rockauto
Honda PAG Oil 4 oz. (found for $30 dollars or so online or at dealers)

Flush out current A/C system (esp lines with condenser removed) and put in new parts above. Leave at high vacuum to remove moisture and make sure system is clean (the longer the system is open to air the longer it should stay to clear out under vac). Add R-134A and you are done!

System should last quite a while! Have mechanic check suction and discharge lines for deterioration and replace as needed! This overhaul of your A/C should make the system last another 11 years.
 

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Discussion Starter #5
Before you spend the money on a compressor replacement, it would be smart to do a direct test of the clutch.

Refer to photo below. It is my CRV, but your MDX will be similar.




The black wire that runs from the grey connector at the bottom of the photo, then between the two Freon pipe connectors is the power wire to the clutch. It's grey connector attaches to another wire that goes to the relay. This connection is usually clipped to the passenger side radiator support flange, with both wires running parallel to the side of the radiator. You are correct that it is a pain to access and disconnect for testing, but it will have to be done if you replace the compressor anyway. It is usually easiest to access by pulling down the plastic splash pan below the radiator. Again, this has to be done anyway. The best way to confirm a bad clutch is to run a jumper wire directly from the battery positive terminal to the clutch wire. If it actuates the clutch, trace the power flow back to the relay. If it still doesn't engage the clutch, proceed with replacing the compressor.
This makes sense. I will give it a try. It could mean the difference between a $50 job and a $1100 job.
 

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Discussion Starter #6
Spend the money on parts and have the mechanic do it!

OEM Denso Condenser with element: $80 rockauto
OEM Denso Compressor: $290 rockauto plus shipping
OEM Denso Expansion Valve: $17 rockauto
Honda PAG Oil 4 oz. (found for $30 dollars or so online or at dealers)

Flush out current A/C system (esp lines with condenser removed) and put in new parts above. Leave at high vacuum to remove moisture and make sure system is clean (the longer the system is open to air the longer it should stay to clear out under vac). Add R-134A and you are done!

System should last quite a while! Have mechanic check suction and discharge lines for deterioration and replace as needed! This overhaul of your A/C should make the system last another 11 years.
If I go this route, I guest it would make more sense to go with the shop that will provide the Denso Compressor, rings and refill for around $1000 since they will be given me warranty on parts and labor. I just have to make sure to get them to vacuum the lines before adding the freon. I will ask them to quote me the expansion valve and the condenser.

BTW, excuse my ignorance but why do I need oil if new Compressor is filled with oil from factory?
 

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Discussion Starter #7
Another question. When jumping the compressor clutch directly from the battery, should I be worried about the polarity of the connector? In other words, can I just connect the ground to one side and the positive to the other and if everything is ok with the clutch it should engage no matter if the cables are in reverse order?
 

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Discussion Starter #8
Another question. When jumping the compressor clutch directly from the battery, should I be worried about the polarity of the connector? In other words, can I just connect the ground to one side and the positive to the other and if everything is ok with the clutch it should engage no matter if the cables are in reverse order?
To Answer my own question, the connector has only a positive lead. No reason to worry about reverse polarity. Negative is provided from the chassis.
 

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Discussion Starter #9
Quick update on my AC issues. I don't have to replace my AC compressor. Uff what a relief. I was having nightmares already about spending 1100 bucks on a AC compressor replacement.

First thing I did was trying @Bluepill suggestion of jumping the Clutch directly. In order to find and remove the AC compressor clutch connector I remove the top engine cover, front grille cover, front splash guard and coolant reservoir. After removing all these things I realized only the top engine cover and the front grille cover needed to be remove (and maybe the AC Condenser Fan if you have big hands)

The connector is right under the alternator on the front part, next to the exhaust manifold, near the oxigen sensor.






After disconnecting the clutch connector, I jumped the relay connector to test the cable leading to the connector. When I discovered the there was voltage on the connector, I was almost fill with resignation I have to replace the compressor. I needed to test the compressor chassis connection to ground, but that was impossible to test without removing the compressor because of the difficult access to the screw. I decided to connect back the connector while the relay pin where jumped. When I heard a click. Voila. I jumped like a kid. The clutch had engaged. I turned the car up to confirm that the compressor was working. And it was however, there was no cold air out of the vents. That could only mean that the refrigerant level was low and the reason the new relay was not engaging the clutch.

Next day I went to the shop because I have already set an appointment. I told them what happen and they confirm the freon was low using the manifold gauge. They said the was almost no refrigerant left so there could be a leak on the system. They added freon and a dye to pin point the leaks. They charged $180 bucks for 23oz of Freon refill and a dye... Never again

I will buy a manifold gauge set at harbor freight and a uv light to monitor the possible leak. They will pay for themselves after the first use.

I wonder if this leak might be coming from the compressor relief valve as stated on the Service Bulletin 11-031 regaring Battery Dead or AC Cools Poorly, since I have had dead battery issues in the recent pass with a battery less than 2 years old.

I will keep you guys posted. Thanks guys for the useful suggestions specially @Bluepill
 

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If I understand your statements correctly, the clutch engaged when you reconnected the wiring back, not your jumper to BAT +? If that correct?


If this is the case, your AC relay contacts are bonded, your compressor was 100% of the time engaged, the system went into overpressure, the Freon escape through the overpressure relief valve. This behavior is documented and the replacement of the AC replay is needed with a new part number from Acura. The new relay has higher current rating contacts to avoid contact bonding/welding by high current. This issue will also drain the batter because the clutch will remain engaged even when the car is OFF.


The clutch will NEVER engage when the system is low on Freon. That is a protection for the compressor. Do not try to manually or externally engage the clutch with low Freon. You will damage the compressor by doing that.


If the AC relay is not the problem, then your leak points are likely to be the fill port valve or the compression fitting on the compressor hoses. By the way, in one of your pictures, one of the compressor connection hoses seems to be wet at the compression union (hose to tubing).


There has been other case in this forum where the leak was in the rear evaporator located inside the center console between the front seats. It was detected with a Freon sniffer. Dye did not help to detect that leak for some unknown reason.


My 2 cents.
 

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If this is the case, your AC relay contacts are bonded, your compressor was 100% of the time engaged, the system went into overpressure, the Freon escape through the overpressure relief valve. This behavior is documented and the replacement of the AC replay is needed with a new part number from Acura. The new relay has higher current rating contacts to avoid contact bonding/welding by high current. This issue will also drain the batter because the clutch will remain engaged even when the car is OFF.

Same issue years ago! At least your relay rattled to let you know it was bad! As stated they usually fuse together and cause a battery drain as Gonzales has stated. Make sure you replace it with the upgraded Relay from Acura.
 

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Discussion Starter #12
If I understand your statements correctly, the clutch engaged when you reconnected the wiring back, not your jumper to BAT +? If that correct?
It engaged when I reconnected the wiring back while the relay port was jumped. I never got the chance to jump the clutch directly.

If this is the case, your AC relay contacts are bonded, your compressor was 100% of the time engaged, the system went into overpressure, the Freon escape through the overpressure relief valve. This behavior is documented and the replacement of the AC replay is needed with a new part number from Acura. The new relay has higher current rating contacts to avoid contact bonding/welding by high current. This issue will also drain the batter because the clutch will remain engaged even when the car is OFF.
Yes, that is what I saw on the service bulletin 11-031. The new recommended part number (relay) is 39794-sda-a03 or 39794-sda-a05

The clutch will NEVER engage when the system is low on Freon. That is a protection for the compressor. Do not try to manually or externally engage the clutch with low Freon. You will damage the compressor by doing that.
You are right. I left it running for about a minute while jumped. I am lucky I didn't damage the compressor.

If the AC relay is not the problem, then your leak points are likely to be the fill port valve or the compression fitting on the compressor hoses. By the way, in one of your pictures, one of the compressor connection hoses seems to be wet at the compression union (hose to tubing).
Last night, I checked the engine bay with a uv light and found a couple of small leaks on the condenser fins, one on the hose to tubing near the firewall (not the one shown in the picture. It might look wet because I detailed the engine and put some dressing on the black plastic and rubber parts), and a big splash on the fill port. I don't know if splash was overflown when refilling the system itself or because the port is leaking.

Is there a way to wash the die away to check if it comes back??

There has been other case in this forum where the leak was in the rear evaporator located inside the center console between the front seats. It was detected with a Freon sniffer. Dye did not help to detect that leak for some unknown reason.


My 2 cents.
Thanks for your input. It's greatly appreciated
 

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Is there a way to wash the die away to check if it comes back??

Thanks for your input. It's greatly appreciated

Yes, there is. Try "FJC 4946 DyeFree Fluorescent Dye Cleaner - 32 oz" or similar at Amazon
 
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Discussion Starter #14
Ended up using mineral spirit with a paint brush. That worked out perfectly. Also used some brake cleaner on the hard to reach spots. Some dye splashed on the plastic and rubber parts and that was very hard to remove. I will try Purple Power foam.
 

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Ended up using mineral spirit with a paint brush. That worked out perfectly. Also used some brake cleaner on the hard to reach spots. Some dye splashed on the plastic and rubber parts and that was very hard to remove. I will try Purple Power foam.

FWIW, for vehicles in Winter Road Salt areas, it is fairly common for the salt to rot the bottom of the condenser over time. It's always the first place I would scan.

Because of age, you may have multiple leaks.

I know that it's not so good for the environment, but in the case of a small leak (holds charge for at least 2 months) at an expensive part. it's cheaper to buy a 30 pound bottle of R134a and keep recharging during the season.
 

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FWIW, for vehicles in Winter Road Salt areas, it is fairly common for the salt to rot the bottom of the condenser over time. It's always the first place I would scan.

Because of age, you may have multiple leaks.

I know that it's not so good for the environment, but in the case of a small leak (holds charge for at least 2 months) at an expensive part. it's cheaper to buy a 30 pound bottle of R134a and keep recharging during the season.
Thanks @Bluepill. So far, I can only confirm a couple of small spots in the middle on the condenser. I haven't seem anything in the bottom of the condenser as of yet. After cleaning the charging port up, it doesn't look like that is an issue. I also don't see anything on the pipe to hose fitting as I previously thought.

If charge holds for 2 months or more, I will definitely keep recharging since we only get to use the AC for a little over 4 months on average.
 

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Replaced Compressor Clutch Relay on my 2008 with 168,000 km (105,000 miles) last week. 3 years since a fluid top up was done. No other air condtng problems in past 80,000 km.
 
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