Intermittent Condenser Fan Mystery.....I've searched :(

gpsports2k · 14 June 2012

<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:TrackMoves/> <w:TrackFormatting/> <w

unctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w

oNotPromoteQF/> <w:LidThemeOther>EN-US</w:LidThemeOther> <w:LidThemeAsian>X-NONE</w:LidThemeAsian> <w:LidThemeComplexScript>X-NONE</w:LidThemeComplexScript> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <w

ontGrowAutofit/> <w:SplitPgBreakAndParaMark/> <w

ontVertAlignCellWithSp/> <w

ontBreakConstrainedForcedTables/> <w

ontVertAlignInTxbx/> <w:Word11KerningPairs/> <w:CachedColBalance/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> <m:mathPr> <m:mathFont m:val="Cambria Math"/> <m:brkBin m:val="before"/> <m:brkBinSub m:val="--"/> <m:smallFrac m:val="off"/> <m:dispDef/> <m:lMargin m:val="0"/> <m:rMargin m:val="0"/> <m:defJc m:val="centerGroup"/> <m:wrapIndent m:val="1440"/> <m:intLim m:val="subSup"/> <m:naryLim m:val="undOvr"/> </m:mathPr></w:WordDocument> </xml><![endif]--> I’ve been searching and reading for the past few hours and can’t find an answer to my issue. Lots of condenser fan discussions but can’t seem to find anyone with the same problem I’m having. So here goes…

My condenser fans are intermittently, turning on and off. Even with the AC off and the car idling, it will sometimes turn on. At times it will turn on/off rapidly, numerous times in a minute. When it rapidly turns on/off, I can hear the condenser relay tick on/off. Imagine a rapidly turning on/off a light switch. Both fans turn on/off at the same time.

When I turn on the AC, it blows cold and both condenser fans come on. When I turn off the AC, the fans will sometimes turn off and sometimes stay on; it will then turn off/on/off/on, pretty much has a mind of it’s own.

Things I’ve checked and verified are good:
* CCU was repaired by BrianK
* Condenser fan FUSES are good.
* Condenser fan RELAY is good.
* Condenser fan MOTORS are good (when they’re on they both blow strong).

Has anyone had a similar issue? Any ideas? Loose connection somewhere? Thanks

PhAnToM · 14 June 2012

I have the same issue. I thought it was a CCU problem so I had the CCU fixed. But it's still the same. What frustrates me is that whenever I get to take to my mechanic, it never seems to replicate the symptoms. When you find a fix, please do let me know. :smile:

dablackgoku1234 · 14 June 2012

Seems like a lot of people are having this problem including myself. It is the Fan Control Unit beside the Main Relay behind the seats. I will be doing some tests and will hopefully be back with some results.

comtec · 15 June 2012

dablackgoku1234 said:
Seems like a lot of people are having this problem including myself. It is the Fan Control Unit beside the Main Relay behind the seats. I will be doing some tests and will hopefully be back with some results.

Yes the fan control unit would be the place to start. The orange/blue stripe wire will be the lead from the control unit that activates the fan relay and the gray/black stripe wire will be the lead from the CCU that provide the fan request. With the AC off, check for a difference in the signal of the gray/black stripe wire when the fans are running and when they are not. If it changes when the fans change then it's probably the CCU, if not then it's probably the fan control unit.

Mike

Briank · 15 June 2012

I had problems with the compressor and condenser fans running on my car for years. I thought is was a issue with connections to the fan control unit but I ended up re-soldering the connector pins to the fan control unit's circuit board and the problem went away. If you are not up to doing the re-solder I would be happy to do it for you for a nominal fee.

NSX2398 · 15 June 2012

Interesting ... this sounds suspiciously like the problem with the main relay where a number of people reported that re-soldering cured the problem. Hopefully this a vibration/wear thing over time .. and not poor quality control .. although if the different circuit boards were sourced from different vendors, it would sort of rule out a common quality issue with soldering.

NSX2398 · 15 June 2012

A link to this thread has been added to the Repairing your NSX part of the Wiki in the Climate Control section in case others have this problem and want to get updates on future developments.

Briank · 15 June 2012

NSX2398 said:
Interesting ... this sounds suspiciously like the problem with the main relay where a number of people reported that re-soldering cured the problem. Hopefully this a vibration/wear thing over time .. and not poor quality control .. although if the different circuit boards were sourced from different vendors, it would sort of rule out a common quality issue with soldering.

"Cold Solder Joints" as they are called are not uncommon. When the boards are wave soldered the larger components just don't get enough heat to make a proper joint and with time and vibration the connection goes bad.

dablackgoku1234 · 15 June 2012

I just resoldered the 12 pins from the plug to the board and it seems like the problem still persists. Would you recommend "baking" it to reflow the board?

Briank · 15 June 2012

No baking will not provide any benefit, there are a couple of capacitors on the board you can replace. I would back probe the connector at pin 4 gray/black wire and see if you are getting a compressor run signal from the CCU. Note it is a negative logic signal, off is on.

gpsports2k · 20 June 2012

Briank said:
No baking will not provide any benefit, there are a couple of capacitors on the board you can replace. I would back probe the connector at pin 4 gray/black wire and see if you are getting a compressor run signal from the CCU. Note it is a negative logic signal, off is on.

Hey Brian, which capacitors do you replace? I'm pretty good with the soldering iron.

Briank · 20 June 2012

gpsports2k said:
Hey Brian, which capacitors do you replace? I'm pretty good with the soldering iron.

Its been years since I replaced the electrolytic capacitors. I think there was 2.

gpsports2k · 20 June 2012

If you remember can you point out which ones in the picture? Thanks

Briank · 20 June 2012

the C4 one

gpsports2k · 20 June 2012

Briank said:
the C4 one

Thank you!

dablackgoku1234 · 20 June 2012

FWIW, I'll chime in on my findings and solution.

I've been having this AC on off thing for a while. When I have the AC on, it cuts out intermittently. When I have the AC off, it kicks in intermittently. I thought it was the CCU, had it repaired, but as it turns out, it was the fan control unit. While the fan control unit is plugged in, the issue corrects itself if I push on the plug hard. Hard enough to slightly bend the plug. If I let go, the problem persists. Every time I push on the plug, it corrects. So, this got me thinking of the 2 possible causes..

1) The connection between the plug and the pins
2) The connection between the pins and the board.

Turns out, it was neither. I bent the pins to get a better contact area with the plug. Didn't help. I resoldered the 12 pins onto the board, didn't help.

So, I decided to "bake" the board (also know as reflow). Some aluminum foil, 385 degree F, 8 mins, solders facing up. Reinstalled it and so far, the problem has not come back. This was a week ago, and I've been driving everyday. When I force the AC on, it stays on and doesn't cut off. When it's forced off, it stays off and doesn't kick in.

EDIT: please know the risks of baking the board. It could be a $150 one way trip.

Briank · 20 June 2012

dablackgoku1234 said:
FWIW, I'll chime in on my findings and solution.

I've been having this AC on off thing for a while. When I have the AC on, it cuts out intermittently. When I have the AC off, it kicks in intermittently. I thought it was the CCU, had it repaired, but as it turns out, it was the fan control unit. While the fan control unit is plugged in, the issue corrects itself if I push on the plug hard. Hard enough to slightly bend the plug. If I let go, the problem persists. Every time I push on the plug, it corrects. So, this got me thinking of the 2 possible causes..

1) The connection between the plug and the pins
2) The connection between the pins and the board.

Turns out, it was neither. I bent the pins to get a better contact area with the plug. Didn't help. I resoldered the 12 pins onto the board, didn't help.

So, I decided to "bake" the board (also know as reflow). Some aluminum foil, 385 degree F, 8 mins, solders facing up. Reinstalled it and so far, the problem has not come back. This was a week ago, and I've been driving everyday. When I force the AC on, it stays on and doesn't cut off. When it's forced off, it stays off and doesn't kick in.

EDIT: please know the risks of baking the board. It could be a $150 one way trip.

I think you still have a solder joint issue, remove the old solder and re-solder. When he solder cracks away from the pin the air that gets in oxidizes the solder and makes it hard for the solder to properly wet to the pin.

Briank · 2 September 2012

My car has had this issue for years. After much trouble shooting and trying different fan control units I finely got the problem fixed. The fan control unit has many cold solder joints. After a complete re-solder the condenser fans and compressor now work correctly, cycling on and off as requested by the CCU.

Eddiep · 3 July 2017

Where is the Aircon Relay

NSX2398 said:
Interesting ... this sounds suspiciously like the problem with the main relay where a number of people reported that re-soldering cured the problem. Hopefully this a vibration/wear thing over time .. and not poor quality control .. although if the different circuit boards were sourced from different vendors, it would sort of rule out a common quality issue with soldering.

Where is this relay located on the car? My Aircon Fans suddenly started to stay on until I switch them off by pressing the aircon button even if the ignition is turned off. The little green light on either of the airflow buttons now also stay on. I have also now experienced a flat battery and after checking it seems something in the car is staying on, but I can find out what it is other than the little green light.

Old Guy · 3 July 2017

Eddiep said:
Where is this relay located on the car? My Aircon Fans suddenly started to stay on until I switch them off by pressing the aircon button even if the ignition is turned off. The little green light on either of the airflow buttons now also stay on. I have also now experienced a flat battery and after checking it seems something in the car is staying on, but I can find out what it is other than the little green light.

Main relay or the fan control unit? Both are on the rear bulkhead (firewall) under the trim panel behind the seats. The exact location moved around a bit between production years. Best to go to the NSX Wiki and get a copy of the service manual that applies to your model year. Presumably your car is RHD so there may be some issues with the applicability of the LHD manuals on the Wiki.

The green light on the airflow buttons - are you talking about the recirc vs fresh air intake control buttons? If so, I think that might be a CCU problem rather than a fan control unit problem.

Kaz-kzukNA1 · 3 July 2017

If you are looking for the location of the Fan Control Unit, please visit this link and scroll down a bit;
http://www.nsxcb.co.uk/blog.php?1811-Kaz-kzukNA1&s=&tag=fan control unit
Basically, it's behind the seat, close to the centre line of the cabin but towards to the left side seat, that is the passenger side for the RHD model.

If you removed your eng bay cooling fan on 91 - 94 MT models or all year models with AT, you may also want to check the eng bay cooling fan relay inside there.
Please refer to post #2 and #6 in this thread; http://www.nsxprime.com/forum/showthread.php/200517-Post-detail-electrical-issues

Have you refurbished your A/C CCU board?
If not, send it to BrianK on here or his website; nsxe-repair.com

I don't know whether you are referring to the blower motor fan, R & L condenser fans or something else when you say the 'Aircon Fans' and I also don't know the year model or spec of your NSX but you may have sticky mechanical relay failure or blower fan Power Tr failure.

After stopping the car and leaving it for a few hours, just listen to any sounds inside the cabin or outside. The obvious sign would be the radiator fan, blower motor fan, etc.
Several owners reported the audio speaker (AMP) relay staying On permanently resulting in flat battery but it's for OEM setup and if you installed aftermarket one, it depends on your ICE setup.
Just listen to the white noise from the speaker but it could be very faint hiss.

For a quick check, you can feel for any warm relays under the bonnet/hood or inside the eng bay.

The power Tr of the blower motor fan is mounted on the side of its housing under the bonnet.

Kaz

Intermittent Condenser Fan Mystery.....I've searched :(

gpsports2k

PhAnToM

dablackgoku1234

comtec

Briank

NSX2398

NSX2398

Briank

dablackgoku1234

Briank

gpsports2k

Briank

gpsports2k

Attachments

Briank

gpsports2k

dablackgoku1234

Briank

Briank

Eddiep

Old Guy

Kaz-kzukNA1

Similar threads