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P80 C70 Hvac Drivers side only hot air, damper motor position, map of position counter, internal pictures

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abscate
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Post by abscate »

It sounds like the blend door is sticking. Do the green LEDs on the ECC control unit flash when you first start the car?
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Post by CoupeC70 »

abscate wrote: 12 Jun 2026, 02:05 It sounds like the blend door is sticking. Do the green LEDs on the ECC control unit flash when you first start the car?
No Red or Green LEDs blinking, everything looks normal.
Will a defective blend door trigger a fault code ?

I could also order a used climate control unit to test it out. What makes me a bit suspicious about mine, though, is that the illumination on the driver-side temperature switch is really poor. Could this potentially be an indicator of a defective temperature switch hmm ?

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Post by abscate »

That’s just a bulb.

The blend door motor plastic does get broken and that would cause your symptoms. There are no codes if the motor drives to where it thinks it should be even if it doesn’t move the blend door
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Post by CoupeC70 »

How does it work with the '850 OBD2' app? Can I actually read the ECC fault codes on a C70, or did I misunderstand the app description?

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Post by scot850 »

I thought 850 OBD2 was only for cars up to 1998 models. Not to be used on later cars.

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Post by jmartin919 »

Works on my 2000 S70 turbo
'00 S70 GLT SE
'82 MB 380SL
'11 MB E350 Sport
'84 Chevy C10
'93 850 GLT NA SOLD

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Post by CoupeC70 »

I pulled ou these error codes:

ECC has 3 DTC: 37 38 2F

ECC-312: Drivers side temp damper motor, no position change

ECC-411: Blower fan motor power unit, Faulty Signal / seized or drawing excess current [or blower fan obstruction, or power stage surge protector problem]

ECC-414: (inlet) Fan motor passenger comp (interior) temp sensor, Faulty Signal

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Post by abscate »

ECC-312: Drivers side temp damper motor, no position change
Bingo!
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Post by CoupeC70 »

Is it defective, or is it no longer working because of the other error codes?

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Post by CoupeC70 »

I cleared the error codes yesterday. Today, no error codes are stored.
I tried several times and also drove the car several times.
Strange...

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