This is a follow on post from my 12/3 post about my 97 850 heat issue. Since then I have cleaned the temp sensors as Klaus suggested and have tried to find the passenger side temperature damper motor. I found that the other day I had very hot air on manual on the pass side then it went cold (seemed to happen as I accelerated). Now, I have no hot air on the pass side and good hot air on the driver side. I suspect a failure of the pass side damper motor assy but would like to see what you all think. Is the damper accessible without taking the entire car apart? I have the glove box out, the knee bolster, the radio and the ecc. I will be replacing the evaporator when I get some time so i will be in there then...I just need to see if I can get some heat in the meantime. Note: this is all happening in manual and auto. Doesn't seem to make a difference.

Mark


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Hopelessly Volvoesque; 91 240, 95 850, 97 850

http://volvospeed.com/vs_forum/index.php/topic/67666-hvac-floor-heat-repair/
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Always willing to listen, just not able to take direction.

Thank you Klaus...you are a faithful volvo warrior.

It looks as if I need to accelerate the replacement of my evaporator to now instead of springtime. Not what I planned on but oh well, the distractions of a volvo love affair.

Thanks for the tips!

Mark, freezing in Indiana.
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Hopelessly Volvoesque; 91 240, 95 850, 97 850

The reason that swapping out the evaporator is that the air circulation box is a single unit. The damper flaps are inside the unit, of course, and not accessible.

You have a possibility of 3 problems:

The ECC temperature control for the passengerside is faulty. This is a pain to fix because the control board is directly behind the face, making removal of the temp selector difficult.

The damper motor works, but the damper is broken and falls down to the cold position. Others have reported that the plastic surrounding the metal rod that the damper is attached to has broken. Fixes have included glue and wire to keep the plastic from slipping. This will not generate an error code, but is a pain to fix. If you find this a problem, before removing the motor from the shaft, turn the passenger heat setting to cold so the motor is matched to the temperature/damper setting.

The temp sensor on the passenger side vent ducting is dead. Most unusual failure and should set a code in the ECC unit and cause the lights to blink.

The damper motor that you are concerned with faces the center console, and is the one that is closer to the firewall. Do NOT allow the damper motor to run while it is not engaged to the damper, it will self destruct and a dealer replacement is about $250 at the dealer.

Klaus

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Always willing to listen, just not able to take direction.