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Discussion Starter · #1 ·
Hi!

Running of out of threads to pull here with this car at the moment. 06 s60 2.5t with about 124,000 on it.

Had the car about two years. In that time HVAC has been a bit troublesome. It always seems to work better on recirculate then vent, dramatically so. The first summer on occasion I would hear what sounded like a damper free itself and then the AC would be nice and cold again. It only did this on occasion. This winter I replaced (with a junkyard part) the recirculation damper and did a full re identify and calibrate. Kind of the same.

I then did a heater core thinking well, maybe I don't have enough heating capacity, again here recirc worked fearsomely hot out of all the vents but was weak as hell with it on vent.

So the blower motor does work, but even when on full it sounds like there's just rushing air around everywhere and when I target even just the middle zone it's not were near as strong as my xc70. I poked the camera into the blower motor area and didn't immediately see anything funky. I even popped the cowl up a bit on the outside of the car and the intake passage seems clear enough. When full fan is requested on the dial it reads 90% in VIDA.

There's a bit of mis-fitment in the center console area where it doesn't quite touch the dash itself below the CCM and radio, not sure if that would really be related though.

As shown in the pictures there was some gunk in there. Did a coolant exchange when I changed it out and put the correct stuff in there. I can tell the radiator was replaced about 2016 2017.

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If the HVAC system works OK on recirculation mode, and not so much when set on outside vent, then I would suspect a clogged up air filter, or some other obstruction in the make up air path. I recently replaced the cabin air filter on my 2005 S60, and I found it to be quite difficult.
 

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Discussion Starter · #3 ·
If the HVAC system works OK on recirculation mode, and not so much when set on outside vent, then I would suspect a clogged up air filter, or some other obstruction in the make up air path. I recently replaced the cabin air filter on my 2005 S60, and I found it to be quite difficult.
I was sort of thinking this as well! I removed the air filter all together thinking maybe I had the wrong one (thick vs the the thin one) or something else was up in there. However it made not discernable difference.
 

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I agree the HVAC system is difficult to troubleshoot, given how it is buried under the dash, and behind the center console. To get any appreciable amount of heat in my 2005 S60, I have to turn the heat on all the way high, turn on the fan, and wait for about 5 minutes as the engine warms up. I suppose there must be mechanical vent flaps, or valves, that open and close, and there must be some urethane foam strip on these valves that either breaks down or loses flexibility over time, leading to reduced air flow. One of these days I will begin taking apart the center console, and try to get a good look at the HVAC system, but that means taking the car apart and not being able to use it for several days. There is also a computer control glitch in my system on the fan control function. Sometimes the fan hesitates to turn on, or the fan motor fails to advance in output as the control knob is advanced. Sometimes the fan motor does not slow down, as the knob is turned down or off. Eventually I can get it to work, but the disconnect between the fan operation and the control mechanism is truly strange.
 

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Discussion Starter · #5 ·
I agree the HVAC system is difficult to troubleshoot, given how it is buried under the dash, and behind the center console. To get any appreciable amount of heat in my 2005 S60, I have to turn the heat on all the way high, turn on the fan, and wait for about 5 minutes as the engine warms up. I suppose there must be mechanical vent flaps, or valves, that open and close, and there must be some urethane foam strip on these valves that either breaks down or loses flexibility over time, leading to reduced air flow. One of these days I will begin taking apart the center console, and try to get a good look at the HVAC system, but that means taking the car apart and not being able to use it for several days. There is also a computer control glitch in my system on the fan control function. Sometimes the fan hesitates to turn on, or the fan motor fails to advance in output as the control knob is advanced. Sometimes the fan motor does not slow down, as the knob is turned down or off. Eventually I can get it to work, but the disconnect between the fan operation and the control mechanism is truly strange.
From the research I've done into my own problem that seems like the exact symptoms of a failing blower motor resistor.
The foam thing is certainly possible. This is a black car that I know lived outside a lot of it's life.
 

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Thanks for the comment regarding your research into the blower control system. I see from looking at U-tube videos that the motor resistor is buried deep inside the HVAC assembly. The actual control knob, and the associated circuit board looks easier to get at. I have noticed that the blower is working normally now that we have cold weather. It could be that a transistor, or an integrated circuit chip, on the HVAC control panel, is actually getting too warm to work normally. Just a guess at this point. I will be looking at both when the weather improves. Too cold to work on the car today-the high is supposed to be about 35 degrees F!
 

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Discussion Starter · #7 ·
Thanks for the comment regarding your research into the blower control system. I see from looking at U-tube videos that the motor resistor is buried deep inside the HVAC assembly. The actual control knob, and the associated circuit board looks easier to get at. I have noticed that the blower is working normally now that we have cold weather. It could be that a transistor, or an integrated circuit chip, on the HVAC control panel, is actually getting too warm to work normally. Just a guess at this point. I will be looking at both when the weather improves. Too cold to work on the car today-the high is supposed to be about 35 degrees F!
Looking at 12 outside today my self. And the car with the better heat is currently sitting without the crank sensor in it due to some poorly setup factory wiring. Best of luck when it comes time. The resistor is indeed apart of the blower motor, they can be separated but they sit inside eh same housing to start with.
 

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You could troubleshoot / confirm a bit more: try removing the air filter altogether as well as the air filter cover. The run the heater on full blast and the heat SHOULD come flying through in the footwell. If it doesn’t, well that means you’ve got a problem upstream of all the baffles, etc (I would think that would be good news).


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Discussion Starter · #10 ·
So I'm getting closer, to address the wooshing air noises that accompany no real heat output, I started finding that a lot of foam behind the dash is sort of not in the right spots sealing the blower motor output to, well, anything. I've push a big piece that's right above the recirculation flap back down in, as well as some around the crossover pipe between the air box and the passenger vent. I think a full dash pull might be in order.

Can the speaker grill from the center come off without the dash? There's no speaker behind it.
 

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So I'm getting closer, to address the wooshing air noises that accompany no real heat output, I started finding that a lot of foam behind the dash is sort of not in the right spots sealing the blower motor output to, well, anything. I've push a big piece that's right above the recirculation flap back down in, as well as some around the crossover pipe between the air box and the passenger vent. I think a full dash pull might be in order.

Can the speaker grill from the center come off without the dash? There's no speaker behind it.
Yes, IIRC you can pry that speaker cover right off. Be gentle though. The mess has a plastic frame. Be sure you are prying on the plastic frame and not the mesh itself when you lever it upwards. I don’t think it’s going to give you access to much though.


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