My heat isn't working....

volvo850kween · Post by **volvo850kween** » 10 Oct 2010, 06:40

Have a 94 Volvo 850 and the thing is there is no hot air -- it blows air but there is not heat. I had the thermostat replaced over the summer because it was running hot now it's not running hot but there is no heat. What else should I have checked??

Post by **MadeInJapan** » 10 Oct 2010, 08:03

Is the fan blowing?

adk793 · Post by **adk793** » 11 Oct 2010, 01:09

Look into the heater control valve and the related parts to it. A basic idea of how it works is, when you turn the knob inside the car to a certain temp/heat, it sends a signal to the valve to open/close (to open or close the flow of coolant) through the system/heater core to then send the hot air into the car. A few components are related to the control valve so check into it. I dont know what its like changing them in these volvos but depending on the location, the hardest thing is just correctly draining the coolant and flushing the system. If it is at easy access, then youre lucky.

Post by **Red-Arrow** » 11 Oct 2010, 04:10

I have a similar issue but I get hot air, Its just its hot when I max it out, one click below max and the air cools down to much.

icelandic · Post by **icelandic** » 11 Oct 2010, 05:37

Afew questions: 1- Do you have manual or electronic ac control? 2- Are you sure that your heater core is not bypassed?

Hot water from the engine circulates full time thru the heater core. All that AC control does is to open or close a flap that directs air thru the heater core and from there to the vents. On the manual AC sometimes a cable that controls such flap needs adjustment. The adjustment procedure can be found at haynes manual. I am not familiar with the electronic control and how it can be adjusted, but in case you have one you can check the codes on the diagnostic unit and they will tell you what is wrong.