Car Heating

[C2NSX]

Hi guys, quick question have seen the threads and searched.

Just serviced my climate control board and replaced all 13 capacitors as 4 were leaking and also repaired some track. Now the fan is working correctly, before only worked on full power.

No hot air is coming through iv looked at the water valve and its stuck in the 18 degree position iv cable tied it in the 32 degree position for testing im getting hot return water down the aluminum pipe but the air is now mild still not warm. I have bleed the system little bit of air but nothing major.

Whats next to check? And if the valve is not opening but moving freely is it something faulty in the dash area or the water valve? Nothing is siezed.

[C2NSX]

Further F-ing about! Did the diagnostics test from NSXprime and only came back with mode control doors not opening correctly.

Just followed the water valve cable back to a small black box under the drivers side and removed the control unit as it doesnt seem to be doing anything. Going to split down and investigate further.

Still only mild/ambient temp air coming out on 32degrees the water valve is fully open and return pipe is very hot. No leaks can be seen from inside the pipes/heater core

***update split the control box apart and the mechanism shot out. Placed it all back in and loosensed it up, everything looks good and nothing damaged motor spins.

[Kaz-kzukNA1]

I’m afraid not enough information so can’t really help.

Seems like you have multiple issues including electrical and non-electrical related.

Before you had the CCU board serviced, were you getting the hot air from the vent even if the fan operated only at the max speed setting?

Did you check with the person who serviced the CCU board on the operation of the four motor driver ICs?

You mentioned that you are 'getting hot return water down the aluminium pipe…..' but how hot was it?
For example, how long can you keep touching the pipe with your finger once the engine has fully warmed up?
If you can keep touching it for more than 5sec, you still have air in the heater core that is part of the cooling system.

How did you bleed the air from the cooling system?
It's a pressurised system with relief valve in the form of tank cap so in order to bleed it, you must remove the cap first.
Obviously, you must set the water valve in Open position before bleeding it at the heater core bleeding point.

Please make sure to understand the difference between the RHD and LHD model when it comes to the water valve operation.
It's installed in opposite direction so don't follow the Workshop manual for LHD model.
The water valve linkage must be pushed all the way towards the cabin in order to open it for the RHD model.


I think this is enough to start with......


Kaz

[C2NSX]

Right just melted my fingers touching the heater core. So this is whats happening so strange.

1. Coolant and water correct level and car gets up to temp correctly and sits around half way had had new pipes,radiator and expansion tank fitted 2010.
2. No leaks level stays correct
3. Water valve is open (32degrees)
4. Infeed to heater core hot/outfeed (aluminium pipe) hot
5. Under the dash heater core is hot on both pipes and the radiator
6. Temp goes very cold if turned down to 18degrees
7. On 32degrees the air is mild would say like around 23degrees is that normal or does the air feel red hot?
8. Climate control has been repaired and tested

[C2NSX]

Before the service was getting cold air and only on full power

tested the circuit board and all seemed fine after service

pipe is too hot to touch for longer than a second

valve is against the fire wall open

bleed the system by removing the expansion tank cap, kept level on max and removed the rubber bung on the return pipe

[Pride]

It might be a case of the climate control unit not sending out the correct temperature setting as shown on the display even though you've had it overhauled, I don't even know if that's possible but worth investigating as everything else seems ok.
Over to you Kaz, is that a possibility???
Jay, who overhauled the climate control module???

[Kaz-kzukNA1]

As in my last post, there is a possibility of two separated issues here.
One is the electronics issue as OP mentioned that the water valve didn’t move.
This could be caused by the air mix motor failure, air mix motor control circuit on the CCU or simply, the control cable (linkage) was not installed properly (this is obviously, not electronics issue).

The other issue is non-electronics related because C2NSX has manually fully opened the water valve by hand probably by disconnecting the control cable from the linkage lever.
However, he seemed to get only mild air temperature above his finger temperature and not red hot air so this is a different issue.


Regardless of temperature setting, fresh or recirc modes selected, any air from the blower motor fan will first enter the evaporator before reaching the heater core.



https://lh3.googleusercontent.com/_gsgP_kTGXQC7LzZY-vcDXV_ZiZbzD7sAAMteWzLJsma6pcbJfTzZKJ2x5MkyN_rHz3l vvT1DY_r5AI7hGDeyYvFSo3AK-YCX3QM9xA5xRSAQb-O0wcyBiMTsVB8eRagn2wUOTlVFFFPW02RkRirsSsdNQqEVpYdK B2-GQE7r4_6HBYaqSr2gFeMZ69BjnbhnKJwyX82ZqT-K8KNomVJtdcflW2kgzBpaThoPO7dwgIddVy5SE-K_0XDO623IpBch6Fw8f5U43C73ZKzSK6MyiyK3OqKhiCtl-KfmutWO5lb3pD66aHJhPwPy1onQLolT0LK3g4cRHWDTMVRyr7a D0DisrrUs9aOwC6_1xq6VLbJ3rmL76iXudDHa8ksT4jz1X5Nd9 bZj1ITbuIHoKrq6T8s8SP1ic7vu0eZsMD71w9whxPtprjtbuGK 1IKVhpNOk-Anrh_HL3bMDDJWexA5uZd6j0aWl7QjSf1-x2Hv2u4VUmUuRfaa89apfDWrrZ21-xZ-pwjeBhVLz7HjcWlVFt29HBBGiUpxdRGHBPbuSHLTWVwFRN3Z-fYQMPt9eD8VbbcMbA=w1080-h608-no

https://lh3.googleusercontent.com/CU8xuUGfa2YKZNcPnjMwisnH31FSPulfFkzEABXBx7RN4RZP3v nXxqkPABS-YRnc6bMVD4FKVnwKKTzvuw3lFOBEpZZ0CmSGaCFlOJkjMtYfR2 VROVQcy9CkJXHWHbDlef8gCX3Dt8uP8isH7jzfx0HDvvZnigoK FboCwZiYqUnViNZtFmFe1D1aFFV9ZvC2nDjxGcXISu7S0Bswbc EawzL8tFSYqWzrVbf3ygZSXjFUV13P_Q-4OfuuuZgne__m0WKNClZUK_GDKghvS2cBh-MzcXhb2ALKQUyAX59nPbggE5PKJJ0NFJ_v_oKhwpi9iutyfaAG RJMrR5rawie8pCm3voM8nirRuv7mXY4-z2XRVV9Dyn_f8rYb65KZz7gdd8gTACs2IpTCzCwO_weuO7ePqK mswsIkjz9tnWO-3QQ-EQHGAB-rnxdYxReO6Cta7KumTBZrEKRpIq5hN0m9hL-3GD_ezm5inisYP7LXwNj663tQQBkqDrgLm5XnVrhK4YdNpXFU5 3COz53JV93vRkPU698is9P9RJS63sGSahAKDaqySNN8qcaoqZT V9AMc7eHcFA=w1080-h608-no
For your reference, under the following setup, the air temperature measured right in front of the centre vent is well over 50degC so it’s red hot.

I have 2 NSX at the moment and both showed the same result.


Outside air temperature: 10degC
CCU Temp setting: 32degC (as mentioned later, it's not actually 32degC. Instead, Honda should have displayed 'MAX'.)
Fan speed: 2nd position from the Min setting as per photo
Fresh/Recirc mode: Fresh
Air mode: Manually selected the VENT mode instead of Heater/Floor air outlet.
Both R & L doors fully opened to minimise the cabin temperature effect.
No wind into the cabin from outside.

Please note that although this won't be shown on the CCU display, when you set the temperature setting at 32degC, it will force the a/c compressor to switch itself Off so no effect of the evaporator unless it was really wet.


By the way, I wrote this on NSX Prime a while ago but Honda really should have displayed MIN/MAX instead of 18/32degC on the display because it’s misleading the owners.
When you set the CCU at 32degC, it doesn’t mean that the target temperature is 1degC above of what you will get when CCU is set at 31degC.


It will force the system into maximum heater operation so it will switch off the a/c compressor, fully open the water valve, heater (foot/floor) air outlet selected, fresh mode selected and either it will be at max fan speed or whatever the fan dial setting that you manually selected.
So, the air temperature coming out of the air vent will depend on the mixture of heater core temperature and the outside air temperature.


If the evaporator fin was covered by lots of debris, then it could affect the amount of air passing through the heater core but not the temperature.

Just a matter of interest, C2NSX, when you are at 32degC, is you’re a/c compressor completely stopped? You can check this by looking at the compressor pulley while the engine is running.
Please be careful with the ACG belt as it’s spinning at high speed.

If the compressor is engaged for some reason, it will lower the air temperature as it’s removing the humidity but not like below your body temperature under above condition.


Kaz

[C2NSX]

Hi Kaz, thanks for that cleared up some confusion. Iv not looked at the compressor but will check.

is there any diagrams of how the routing of the water system runs? If no leaks and all the pipes are red hot inside the cabin (under the dash) then is it just air passing through this being heated?

edit: just seen a diagram of where the evaporator is right in front of the heater core i see now. Will take my air box off and feel this guessing if its cold then the aircon compressor is running and in turn chilling the air more before it gets to the heater core? If im correct in thinking that makes sense.

[britlude]

as Kaz said, could it be the air 'mixer' doors inside the heater unit not being driven/faulty.

if they are set to full off, they cover the hot matrix so no air flows through it, so it won't matter how hot the matrix is, it won't heat any air...

[Kaz-kzukNA1]

Was hoping for C2NSX to carry out the same testing as per my last post using the Vent motor as his Mode control was not working and triggering the error indicator during the Self Diag test but Jonathan has explained the reason.
Nice one :D
Hope you can find out whether it was caused by the Air Mix motor and/or Mode motor itself, the damper doors mechanically stuck closed or gear/linkage just broken.
By the way, you have removed the Air Mix motor itself and opened it. After placing it back on the heater unit, you mentioned that 'Placed it all back in and loosensed it up, everything looks good and nothing damaged motor spins'.
Did you mean your water valve control is now fixed (somehow???) and also the heater damper/doors is moving up/down and working fine?

Not sure whether you managed to fix the water valve control or not but hope you can sort out the climate control soon.
I need to sort out my evaporator as well....


Kaz

[C2NSX]

Ahhh didnt know the motor doors shut will prevent the heat coming through. When i press mode it changes to window and face but not feet.

The air mix motor controls the water valve i opened moves freely but not getting a signal to open. Guessing if this doesnt open the bottom door no hot air will come through?

[Kaz-kzukNA1]

I think you got bit confused with some of the motor operation.

There are 4 motor driver ICs on the CCU.
Mode, Vent, Air Mix and the Fresh/Recirc.

Mode and Vent motors will select one of the six air outlet modes but you already mentioned that you can’t select the feet (floor) air outlet controlled by the Mode motor so I’ll leave this for now.

Fresh/Recirc motor is as it says. It will open/close the shutter door mounted on the blower motor housing to let the ‘fresh’ air from outside or ‘recirculate’ the cabin air by the means of blower motor fan into/inside the cabin.

The Air Mix motor does control not only the water valve but also the position of the heater damper/doors and this will decide the air temperature blown into the cabin.


This is the reason why asked you the question in my last post when you removed and re-installed the air mix motor assy.
This is nothing to do with the Mode motor that you triggered the error indicator in the Self Diag test.

Strange that it didn’t trigger the Air Mix motor error as well unless the CCU IC didn’t send out the open command when at max temperature setting test.

From what you wrote so far, neither the water valve control nor the heater damper/doors were working and on top of this, you seem to have Mode motor related issue that can’t select the floor air outlet.

As you were saying that the CCU board was tested fine, sounds like someone worked inside the cabin in the past and may be disconnected wiring connectors or placed extra wires/objects that jammed the gear/linkage movement although the heater damper/door linkage is inside the heater unit and only behind the air mix motor unit so not easy to obstruct it...


Kaz

[britlude]

for reference, the air-mix doors are buried inside the heater unit....

http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0996b43f/80/22/f9/b4/medium/0996b43f8022f9b4.gif

[C2NSX]

Thanks both of you, makes total sense now. There was an old phone installed right below the air mix motor control so not sure if this is whats caused some issue in the past.

Kaz if the CCU is causing the issue is this something you can test for? Just so i can be 100% sure

[C2NSX]

From looking the air mix motor looks okay but is no movement from this if i adjust the temperature from the CCU.

[Kaz-kzukNA1]

Thank you for the diagram, Jonathan.

C2NSX, as you managed to remove the air mix motor unit previously, if you have small enough finger like me, you can open as well as close the heater damper/doors by rotating the centre shaft that you can see in Jonathan's diagram.
You can access it at the bottom of the heater unit where the air mix motor is fixed. Obviously, you need to remove the air mix motor again.
There is cross shaped cut out on the motor where you insert the centre shaft. I'll try to take a photo later as I need to remove the floor carpet for one owner any way.

As mentioned above, I don't think you can obstruct the operation there so may be you have electrical wire damage???

In the past, I know one owner didn't push in far enough one of the green connector at the back of the CCU and this caused intermittent connection on a certain circuit resulting in abnormal operation of CCU.
He reported me the issue after I refurbished the CCU board for him but since each CCU boards were tested using my NSX and knowing that everything operated fine, we knew it was something to do on his NSX and thus, he found out the loose connection at the back of the CCU.
You may want to check it as well.

Also, did you try testing the air mix motor as in the workshop manual?
If it doesn't rotate when 12V applied, you found one issue although very unlikely to fail unless something jammed the operation and overloaded the motor.

Kaz

[C2NSX]

Yes know exactly what your talking about turning to open the flaps. Yes 12v applied and the little motor span fine. Part from changing the capacitors and repairing track is there any other components that tend to fail?

For now as being spring/summer soon not a major issue so will continue when i get chance for following through with further testing and if i can find someone local with a good CCU fo try on mine. But will manual open the doors to see if heat does come through.

[Kaz-kzukNA1]

https://lh3.googleusercontent.com/_sBMmi6AVPr3Vs_LSFIB8BgNUFntLKs4aR-33T_3eZd_hry_hnF_De_tqG6KKSctzwyjXpaHEVLXow4jhc7qw s8uvCY1FJhjfBhgSbl7wh7HeRpormqx-ZYt0Sgwmy7rdD1if4m48CG3bGCQvaKeO2FRFp4_XY-r4JC_FUQ-XP5OqXq6ua7v0NwN__luCjJUyJtgsDlCG0yiG9INLftbOPbYzK XEtJxNAMHehlT4RRr20HmyanP03w4-wHGCe94eoO7m-RKUjCYa_TL17u75AMvxhIb2FfWBNjPyTBMipQfqoFShgosgVop aTB8GAot-eHfP9TeOYYyleAF1IYBmuLAmH8Dz4X4jlEmlHOnqr7SCeFMNTS nC6qElh3zBBJSIjjsc8LDVrNH7yX17AN8blGTxbE7Jl39UuYBk HUQomt8lIwVB6wicSHurmXGDFJOS97_Fo4kMVbORlMNiy7P4sZ WmBcLvysii9FSbkpZyEGZg7y7aZTrYaN0IqSOAS7hmmNcsgnu3 xRev9U8H-TZfZi5FQkyxwgSLbuFuMn75cp5ofnls3x01rAsnGQsh5Rq-rYtjtA=w1080-h810-no
Probably no longer required but for future reference…..

This is the Air Mix motor removed after the CCU settled at temperature setting at 18degC.
Even after you removed the Air Mix motor, you can still achieve the same (if your CCU is operating properly) by reconnecting the electrical connector, set the temperature at 18degC and turn IG key into On position.
Once the cable lever reaches this position, the CCU board tells the motor driver IC to stop the motor so it won't keep spinning and applying excessive force to the heater damper/doors.

This is for the RHD, by the way.

The cross cut out has one narrower channel so you must line it up with the centre shaft of the heater damper/doors.

The Air Mix motor is mounted at the bottom of the Heater unit and in this photo, we are looking down into the upper plane of the motor unit when it's installed at the bottom of the heater unit.

As mentioned previously, if you lie down on the floor facing the ceiling and looking into the bottom side of the Heater unit, you need to turn the centre shaft in clockwise direction as far as possible in order to close the heater damper/doors before installing the Air Mix motor when it’s in the state as per photo. Again, please don't confuse yourself with the direction of the motor as it will be the opposite of the above photo when you are looking up the ceiling.

If you want to test your heater core and if the motor is still working, you could just apply 12V to turn the centre shaft.
If it moved to the opposite direction, just reverse the polarity but make sure to Close the door and set the Air Mix motor to COLD position before re-installing it as you will need to adjust the water valve control cable and you really need to have water valve closed 100% to prevent mild air when you want freezing cold air.

Good luck.

Kaz

[C2NSX]

Thanks Kaz, great help