Interesting Climate Control Behavior Topic is solved

a3inverter · Post by **a3inverter** » 11 Oct 2018, 17:39

All,

As the weather is getting cooler I notice an interesting behavior with the climate control system in my 2006 V70. I purchased this wagon in the summer and briefly tested the heat during the test drive.

Basically, the only way to get heat out of the vents is to crank the temp knobs all the way to the right...to the highest setting. If I turn them counter-clockwise one click from the high temp limit, it starts blowing cold again.

Any thoughts?

Post by **abscate** » 11 Oct 2018, 17:43

Sounds like the dampers have lost calibration.

On these cars, the heater core flows full on all the time. And temp is adjusted by mixing cold and hot air by air door movement

All of this presumes you have the auto climate System, not the base manual one.

a3inverter · Post by **a3inverter** » 11 Oct 2018, 17:56

Looks like this one:

http://www.justparts.com/Auto_Parts/Tem ... 4/21990880

I don't know if that's the base version or the deluxe...

Post by **oragex** » 11 Oct 2018, 19:00

Thats the automatic. So you can put the automatic button either on - green light, or off - red light.

Look first near the right temp knob, behind the grid is the cabin temp sensor. Put the vacuum on it or blow some air but dont touch the sensor.

Next try the calibration mentioned, is it done with the Vida software.

Post by **abscate** » 12 Oct 2018, 02:17

Thanks orangex, forgot about sensor cleaning. Step one!

a3inverter · Post by **a3inverter** » 12 Oct 2018, 05:01

Actually, it turns out that I had cleaned the sensor a month or so ago with a vacuum as it had grown a thick coating of dust. I didn't touch the sensor itself. Just this morning I blew some air from my compressor on it and will report back.

a3inverter · Post by **a3inverter** » 24 Oct 2018, 04:49

Update: This was user error. If I turn on AUTO mode and set the temp, everything works as expected. AUTO mode seems to automatically turn on the A/C, which I can then turn off unless I need it to demist the front windshield.

Post by **abscate** » 25 Oct 2018, 02:29

It should be sticky, that is, if you turn off the AC manually, the next time you use the car it should stay off.

The defrost mode always turns on AC

Post by **Rattnalle** » 25 Oct 2018, 03:06

abscate wrote: ↑25 Oct 2018, 02:29 It should be sticky, that is, if you turn off the AC manually, the next time you use the car it should stay off.

The defrost mode always turns on AC

You shouldn't turn the AC off though. That button is only useful when driving with the windows down in summer.

But yes it should stay off if you do turn it iff.

a3inverter · Post by **a3inverter** » 19 Dec 2018, 07:37

Interestingly, this behavior seems to be back after a battery replacement (the 9 year old Volvo battery gave up the ghost after the guys at the local tire place ran it down listening to tunes whilst putting on new tires). Specifically, it's nice and warm for the first 20 minutes or so (set to Auto, A/C off and set to 72F or so), then it starts blowing cold out of the vents. I can still crank it to full heat (all the way clockwise) and it starts blasting hot air, but I understand that to be sort of a manual override. If I reduce the temp down to a lower temp I can definitely feel the cold air blowing out of the vents get colder, so I think there is some amount of control going on.

I followed all the appropriate procedures when replacing the battery (position II when reconnecting the (-) lead, etc.) and also did some futzing with the radio/ECC to get the Bluetooth adapter in, but never disconnected the ECC (only the radio).

All other functions on the ECC (seat heaters, fan, recirc, defrost, etc.) all seem to be working fine. Sunroof and locks work fine and no messages were generated.

Given that I can get heat, I don't think there's an issue with the coolant or heater core, but did notice when cold that the coolant is at the lower mark on the reservoir.

I had previously addressed some dust in the thermistor vent, but perhaps there's a clog down in there that I didn't get to. When I do that I'll also check that the wires for the thermistor aren't broken.

Any other thoughts?