('98 v70) no heat from center vents

Guest · Post by **Guest** » 03 Feb 2006, 11:44

Hey folks,

I found this forum looking to track down a problem, and am I glad I did! This looks like the place!

Here's the story.

I noticed the other day, when I want heat, (it's cold here in the AM), I do not get ANY heat from the center vents, yet I get plenty of hot air coming out of the side vents.

I've seen the posts where people who are gettting NO heat, need to replace the thermostat, but nothing that seems to address the combination I am seeing.

Additionally, the blowing air now seems to be "all or none." The air barely moves when I have everything set to "auto" and I adjust the degrees. If I turn the dial onto "max" when it blows out full force. Currently the dial for degrees does not seem to be working as designed.

I saw another post on another forum for the 2001+ XC's and someone had this exact problem and they had to clean the cabin temp. sensor intake and it fixed the problem, and they even posted a PDF of how to do this, but the PDF was instructions for the newer XC, which at afirst glance doesn't apply to my car.

Any ideas?

Thanks again!
Jeff

tortio · Post by **tortio** » 03 Feb 2006, 11:47

Hey folks,

I thought I was logged in when I posted this thread, but the original post is mine.

Thanks and sorry!

White850Turbo · Post by **White850Turbo** » 03 Feb 2006, 15:49

I don't have a ton of personal experience with climate control systems on these cars thankfully, but I do know that the symptoms you're experiencing are often related to the cabin temperature sensors. Assuming the XC70 is the same as the 850/S70, the sensors should be behind the "oh s#&%!" handles.

steve3007 · Post by **steve3007** » 04 Feb 2006, 18:15

Do the orange lights on the climate controls flash when you first start the car? If so, there is a fault somewhere in the ECC system. Unfortunately, it is tough to diagnose without a Volvo diagnostic tool. You might have the local dealer run their diagnostics - it could a damper control that just needs to be calibrated.

tortio · Post by **tortio** » 09 Feb 2006, 08:47

steve3007 wrote:Do the orange lights on the climate controls flash when you first start the car? If so, there is a fault somewhere in the ECC system. Unfortunately, it is tough to diagnose without a Volvo diagnostic tool. You might have the local dealer run their diagnostics - it could a damper control that just needs to be calibrated.

You know, I remember seeing the lights blink like that in the summer when it was super hot. But this time of year, no they aren't blinking.

I think I have more info. Someone else pointed out that I should try moving around the "fresh air mix" dial next to the center vents. So, if I turn off the "fresh air mix" and have the heat come out, you can hear the airflow being restricted but warm air does indeed come out, but very lightly.

If I turn on the "fresh air mix" on full blast, the restrictive sound goes away but only cold air comes out.

So now I think that there might be dampener not opening. So my new theory is that since I had the heat on, yet very cold air was blowing in, the temp sensor was trying to compensate by have the incoming fan on full blast.

What do you guys think? Is this something I could fix myself?

I will dig around on the forum with this new info and see if I can find something that applies. Thanks for the warm welcome and advice.

Thanks,
Jeff

steve3007 · Post by **steve3007** » 09 Feb 2006, 10:09

My 98 V70 and also my 95 850 both do the same thing - low warm air flow from the center vents. I have always kept the fresh air mix down to ~30% and I get enough (but not alot of) warm air out.

Fortunately, Seattle area does not get too cold so I don't need it as much as if I lived in a colder climate.

Is this a characteristic of these cars? But until I need a better reason to get in behind the dash, I can live with it.

tortio · Post by **tortio** » 09 Feb 2006, 11:30

Our just started doing this so I don't think it is normal.

And you bring up a good point. I don't know how difficult it would be to fix this DIY. I'm also due for a service here this week. It seems like everytime I take th v70 into the shop in addition to whatever I am already having done, I always spend ~$300 on something else.

If I get more info, I'll post a follow up; maybe it's not that hard to fix.

Thanks again.

steve3007 · Post by **steve3007** » 09 Feb 2006, 13:05

If you're going into the shop, it'd be worth having the mechanic do a quick diagnosis (pull the codes with the VADIS tool) and decide whether to have them fix it or DIY.

At least the diagnosis will tell you if any codes are present (that you can't see with standard OBD2 readers since they are Volvo specific).