New 05 coupe

SP250

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Air con is variable speed achieved by 2 fans 1st relay is low speed 2nd relay kicks in 2nd fan at low and then high speed.

The relays are near the expansion tank.
Have a look at page 150 of the manual of later manuals. Its page 163 i think in earlier manuals.

You also have a fuse for each fan on the bulk head left hand side fuses 3 and 4.
We are talking about interior fan, for A/C
 

CatmanV2

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48,547
We are talking about interior fan, for A/C

I'd follow @spkennyuk steps just to validate, but looking at my copy of the manual I don't think those relays are impacting the internal blower. I can't find anything better in the 'workshop manual' I have though :(

C
 

CatmanV2

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48,547
Thanks for trying CatmanV2

FWIW (at this point, probably not much) I suspect the input from the control knob is taken by the A/C ECU and converted into a motor output.

One question I didn't ask is 'does the display of motor speed change' when you twist the knob? Given that there is no alteration in blower motor speed (and not withstanding the relay possibility) when the A/C is in automatic and temperature is changed I'm going to guess 'no' and further guess that the issue lies with the A/C ECU and its output to the blower.

As ever, when I over reach logic, I reserve the right to be talking utter **** (1) and be totally wrong.

C

(1) Please see the terms and conditions of interacting with the entity 'CatmanV2' where you will see that this is accepted state, and overrides all other considerations ;)
 
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SP250

New Member
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FWIW (at this point, probably not much) I suspect the input from the control knob is taken by the A/C ECU and converted into a motor output.

One question I didn't ask is 'does the display of motor speed change' when you twist the knob? Given that there is no alteration in blower motor speed (and not withstanding the relay possibility) when the A/C is in automatic and temperature is changed I'm going to guess 'no' and further guess that the issue lies with the A/C ECU and its output to the blower.

As ever, when I over reach logic, I reserve the right to be talking utter **** (1) and be totally wrong.

C

(1) Please see the terms and conditions of interacting with the entity 'CatmanV2' where you will see that this is accepted state, and overrides all other considerations ;)
No change in display of fan speed. Do you know location of A/C ECU
 

Oishi

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Messages
825
It's #3 in the diagram. Only $3070 for it. Mine is a bit dodgy, the fan knob will randomly refuse the office.
88651
 

spkennyuk

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5,932
No change in display of fan speed. Do you know location of A/C ECU

Thats info we didnt have.

There are resistors on the internal blower fan but if that is failing you should get an error code of AA75. Which your not getting.

Thats potentially good news as if the resistor is failing it is moulded in the the fan housing and a dashboard out job to fix.

I would be tempted to take the rotary dials out and open the back up and clean up with some contact cleaner.

If the display isnt showing the increase in fan speed requested then it does point to the fan speed controller being the issue.
 

SP250

New Member
Messages
14
Thats info we didnt have.

There are resistors on the internal blower fan but if that is failing you should get an error code of AA75. Which your not getting.

Thats potentially good news as if the resistor is failing it is moulded in the the fan housing and a dashboard out job to fix.

I would be tempted to take the rotary dials out and open the back up and clean up with some contact cleaner.

If the display isnt showing the increase in fan speed requested then it does point to the fan speed controller being the issue.
Im confused, are you saying, its good news if the dashboard needs to come out? How go you take out the rotary dials? Thanks for the info
 

SP250

New Member
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14
Im confused, are you saying, its good news if the dashboard needs to come out? How go you take out the rotary dials? Thanks for the info
Sorry, just realized, your saying its probably not the resistor, which would be a “dashboard out job”. I was thinking the fan switch needs to be replaced, which I assume is a dashboard out job. But I would like to try cleaning first, if you could describe the process
 

spkennyuk

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5,932
Im confused, are you saying, its good news if the dashboard needs to come out? How go you take out the rotary dials? Thanks for the info

No. Im saying if the resistor on the internal fan is failing you should of seen an error code AA75 on the display. Your not getting that and the only way to replace that resistor is to take the dash board out. Around 10 hours work for a $1 part.

What your describing isnt restricted to the aircon side of the system. If you press the eco button i take it the display doesnt show the increase in fan speed requested either ? It is staying on the low setting regardless of aircon on or off ?

If thats the case then it is pointing to the rotary knobs that control the vents and fans being the issue.

To remove those you need to take the screen out and then there are 2 screws that hold them in place.

If you change which direction the air is blowing from upper to mid to floor vents is the direction changing ?
 

spkennyuk

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5,932
Removal instructions here
 

Attachments

  • Center Console Radio and Control Removal (1).pdf
    4.5 MB · Views: 21

SP250

New Member
Messages
14
No. Im saying if the resistor on the internal fan is failing you should of seen an error code AA75 on the display. Your not getting that and the only way to replace that resistor is to take the dash board out. Around 10 hours work for a $1 part.

What your describing isnt restricted to the aircon side of the system. If you press the eco button i take it the display doesnt show the increase in fan speed requested either ? It is staying on the low setting regardless of aircon on or off ?

If thats the case then it is pointing to the rotary knobs that control the vents and fans being the issue.

To remove those you need to take the screen out and then there are 2 screws that hold them in place.

If you change which direction the air is blowing from upper to mid to floor vents is the direction changing ?
Econ button does not change fan speed.If I change fan direction, it stops coming out of vents (minimal air come out of other vents) I assume because its on low. Is it difficult to remove screen?
 

spkennyuk

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5,932
Econ button does not change fan speed.If I change fan direction, it stops coming out of vents (minimal air come out of other vents) I assume because its on low. Is it difficult to remove screen?

The screen is easy to remove it prises out but follow the instructions on the pdf i uploaded above.

Only thing you have to be careful of is protect the trim surrounding the screen as you can dent it and use plastic trim removal tools to lever the screen up. Its on 4 metal pins if i remember correctly.

You may even be able to get a replacement rotary controller. Its probably a bosh part and if your handy with a soldering iron you may be able to remove and replace just the rotary controller.

The reason i asked if the direction the air flows to which vents can be changed which your saying it can tells me that side of the climate control module is working correctly.
 

SP250

New Member
Messages
14
The screen is easy to remove it prises out but follow the instructions on the pdf i uploaded above.

Only thing you have to be careful of is protect the trim surrounding the screen as you can dent it and use plastic trim removal tools to lever the screen up. Its on 4 metal pins if i remember correctly.

You may even be able to get a replacement rotary controller. Its probably a bosh part and if your handy with a soldering iron you may be able to remove and replace just the rotary controller.

The reason i asked if the direction the air flows to which vents can be changed which your saying it can tells me that side of the climate control module is working correctly.
Thank you for your help,I was able to dissemble the dash and found the plastic stick inside the fan knob was broken. Glue it back on and reassembled the center console. All good! Not an easy job,but I could not find a replacement ecu fan unit anywhere. And the are quite expensive. Thanks again spkenney!
 

spkennyuk

Member
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5,932
Thank you for your help,I was able to dissemble the dash and found the plastic stick inside the fan knob was broken. Glue it back on and reassembled the center console. All good! Not an easy job,but I could not find a replacement ecu fan unit anywhere. And the are quite expensive. Thanks again spkenney!

Your very welcome. The rotary control bit will most likely a shared part with other car companies. If it breaks again look for a part number on it and will see if i can track one down.

I suspect its a bosch part.

Glad its all sorted with little expense.