Its 105.2 in Houston, so all I think about is heat, seriously this problem comes up when I drive to where it is cold, we have suffered from this strange heat no heat in the car; above 32 degrees (or less) plenty of heat, but when it gets below 32 degrees (or a little less) the heater seems to cut way back and will only blow out a little heat, not near enough. You can feel the heat in the dash back in there (new heater coil). I am guessing this is a sensor problem, but where which one?

 

Hello, Does the temperature gauge read "normal"? How old is the car (and thermostat)? That it can put out heat at or above 32 degrees suggests that the blend door is working. Kira

 

engine temp is normal, when the outside temp gets above 27 to 32 heat blasts out. I am not remembering the actual temp where it quits heating like normal, so I am not being specific, but it is below freezing. Its a 98 V70 You can feel heat in the dash (by touching it) near the heater controls there is heat back there behind the controls but it does not come out the vents

 

I have the same problem, and it has nothing to do with the heater core or thermostat. Any time the temp is below 32 degrees, none of the lights on the ECC come on, and pressing the buttons or sliding fan control does nothing. As soon as inside of car gets above 32 degrees the ECC buttons all light up and the fan starts blowing hot air. It has to be some kind of problem with the sensor that prevents the AC from operating below freezing, is also preventing the heater from operating below freezing, since as i stated no lights on the ECC come on what so ever.

Anyone have any suggestions?

 

This very thing just started happening to me.

I was working slightly north of Toronto, where it was around 32F according to the dash temp.

The engine temp gauge for most of the trip home was way below normal, just hovering above the minimum.

As the outside air started to warm, (the further south I drove) so too did the engine temp. When I got home, it was in normal operating range. Had it not been for the seat warmer, it'd be a chilly ride home. This was about a 40 minute trip. outside air in Toronto, was about 35F when I got home.

I have to drive 2000km in a couple weeks in cold climes, anyone able to offer some theories?

Thanks, Terry

 

Terry, if your motor doesn't warm above 135 degrees, the automatic climate control will not allow the heat to come on. I have a real temp gauge connected to my car and as soon as the coolant temp reaches 135 my heat comes on.

So, if your car is not warming up properly, you need to replace your thermostat.

 

Thanks for the feedback everyone.

Since I live in Canada, my online parts source lists a Calorstat at 92C and 87C or a BEHR at 92C ??

I will also check a Volvo dealer as well.

 

I think I use the 92.

 

I have to disagree with this analysis. The climate control lights have always lit up, regardless of the engine temp. The problem we are describing has nothing to do with not getting hot air out of the vents(thermostat problem). You cant even turn the fan on period, and neither the inside/outside or the ac on/off lights will light up.
Typically when you start the car either in summer or winter, both those lights light up, and you can immediately turn the fan on, regardless of engine temp. With this problem, below freezing the fan will not come on and the ecc has no power until temp gets above 32 degrees. I believe it has something to do with the sensor that turns on the little snowflake light on dash panel to let you know its freezing temps outside. when that light is on heater will not function at all.

 

My apologies for contaminating the thread. In my case, the heater fan works and I get the little snowflake on the dash. If the engine temp is low, so is the air coming out of the heater.

Yesterday, the temp in the garage where the car was overnight, was 54F. Driving to the job site, the outside air, eventually dropped to around 28-34F. The car ran fine, in proper temp range and the heat was OK. On the way home, the temp was 34F to 32F car took a lot longer to, but eventually did come up to normal range, with it seemed minor lower temps with changes to outside air.

PS: What does the ECC mean?

 

ECC means Electronic Climate Control. Dial in a temp and the car will do all it can to maintain that temp and even control the fan speed as necessary.

IceRacer and Brew, what model cars do you have?

@ IceRacer: I would change the engine thermostat and see if that helps. A cold engine wears faster, runs rich (waste gas) and doesn't warm up the cabin good.

 

RSPI....I have 98 V70, same as cablejohn above who has the same problem and never got answered. Yes you can feel small amount of warm or hotare coming out the vents, but this is just outside air getting past vent door seals and getting heated by the heater core. The problem is you can not turn the fan on at all. None ofthe ECC controls are operational until the temp warms up. As son as that occurs the lights on the ECC come on and all the controls are operational again.

 

I changed the clearly broken t stat yesterday with an OEM Wahler.
The t stat bracket which holds the spring on the underside had broken, I'll post a pic once I find my camera.

The DOM stamped on the broken t stat was 08 03, so at some point it had been changed.
The new t stat is a 90 c right from the dealer.

It runs like new again, heater nice and toasty.

For the record, my heater controls ie: fan motor and such always worked during this.

As an aside, while driving home last night, I hit a pc of 6x6 fence post about 12 inches long that crashed its way along the underside of the car......can't wait to see the mess it made. Good sign though, no fluids under the car this morning, fingers crossed.

 

Hey Brew, I answered IceRacer because I thought his problem was different from yours & Cable Drews. I do not know what is wrong with your system and have not seen any other post anywhere to help you with it. If I learn of a solution I'll be glad to share it here.

 

thought I'd post a pic of the broken t stat I found in my car.

put a new one and it is nice and toasty again....