Air Only Blows to the Windshield - Hot or Cold

Post by **songzunhuang** » 23 Jun 2023, 21:30

For many years, my 1998 V70 T5 would periodically make a tapping sound in the center of the dash. Things still worked so I didn't worry about it. Well many months ago, I noticed that the air only blew up to the windshield through the defrost vents on top of the dash. It doesn't matter if it's air conditioning or heat, it blows to the windshield.

I have noticed the climate control LEDs blink on occasion, but then stop after a while. I can try turn the controls to direct air from the front of the dash or to the windshield and it just blows to the windshield.

From my research, I am thinking it is an electric damper motor or one of the plastic ends for the metal rods that may have failed? The question is, which one? I know there are 2 damper motors on the drivers and passenger sides. I think there's another accessible through the glovebox to the right for the recirculation.

Does anyone know which motor I should check or if my climate control head unit is bad? What are the ways I can check this?
Thanks in advance for any guidance.

Post by **abscate** » 24 Jun 2023, 03:12

Five motors on a -1998+ model, there is a chassis break in 1999 which went to four motors

Driver temp damper
Passenger temp damper
Ventilationdampervleft
Distribution damper right ( your problem, I think)
Fresh/recirc damper in front of glovebox

Post by **jreed** » 24 Jun 2023, 06:56

Have you had a chance yet to try reading the error codes stored in the ECC? That can be a helpful starting point for diagnosing the source of the problem. One type of code reader you can build cheap and try:

viewtopic.php?f=1&t=50443&start=13

WhatAmIDoing · Post by **WhatAmIDoing** » 24 Jun 2023, 14:00

I had a 99 S70 stuck on full heat defrost only. The ECC unit was bad and not the motors like I thought. The Volvo 850 app and an ELM327 OBD2 adapter can read stored ECC codes. There was a recent update that gives you the ability to reset and reprogram climate control motors that have stroked out. It's still possible the gear on the motor has stripped out, but easy stuff first before pulling the dash apart.

Post by **abscate** » 24 Jun 2023, 14:07

Be careful and scour Fora before resetting v70 ECC control units. It is not hard to brick them.

WhatAmIDoing · Post by **WhatAmIDoing** » 24 Jun 2023, 14:14

abscate wrote: ↑24 Jun 2023, 14:07 Be careful and scour Fora before resetting v70 ECC control units. It is not hard to brick them.

Actually, unless I misunderstood xiaotec's changelog, the app can now unbrick ECC units. Need to try this on my bricked one.

Post by **songzunhuang** » 24 Jun 2023, 21:25

So today I went and removed the glovebox and to gain access to the electric damper motor. I read that the lithium grease could mess up some contacts and thought I might clean them. When I removed the glovebox, this is what I see. Is the motor in the picture, pointed at by the red arrow, the one that controls the airflow from the windshield to the front of the dash?

: Peeking in from the glovebox.; Electric Damper.png (1.06 MiB) Viewed 407 times

It looks like it could be a tricky removal so I want to be sure before I go at it. If someone could verify, that would be great.

I did run the system and can at least verify that the recirculation motor is working fine.
One thing that surprised me a bit is the black shaft end with the square. I thought there was supposed to be another damper motor that connects to that? As you can see, there's no motor there. Perhaps my car only have 4 motors?

Also, for good measure, I bought a used ECC from eBay. Maybe it'll fix all this after all.
I'll get to the bottom of this, but I am bracing for a long journey.

Post by **FireFox31** » 24 Jun 2023, 22:53

Here's a servo diagram for a 1998 850. As abscate said, there is one fewer servo in 1999- (because they combined two?).

Looks like your picture is the passenger's side temp damper motor (and the driver's side is identically diagonal on the other side of the center console, visible with the knee panel removed). My notes say that in 1999-, the floor/defrost motor was combined with the left vent damper motor. Since I don't see the right floor/defrost, is it possible that yours was combined in 1998? Regardless, I recall it being easy to pull the driver's knee panel and see the two dampers there.

My floor/defrost is broken in my 2000. VIDA stores codes showing that it's not working how it should. Doesn't help for 1998, but maybe the 850 scanner app could show similar info.

Post by **scot850** » 25 Jun 2023, 02:24

850's used to have a motor on that end. There is one on the driver's side that turns that shaft. The black item behind that is a servo motor so you are correct in your assumption. If you remove it (I can't recall the size of Torx screw, T15 or 20? It is not 'fun' extricating that motor as you need to be bendy and it is hard to see the screws. A mirror on a tick with a built in light may help. I can't now recall if I used a bendy stick with a Torx bit on it to get into the screws. Last did that a long time ago.

Once you have the motor out, mark the position of the motor shaft flats to the motor case so if you try to test it with a 9V battery, you can make sure you get it back to the correct position before re-installing.

Neil.

Post by **songzunhuang** » 25 Jun 2023, 11:43

FireFox31 wrote: ↑24 Jun 2023, 22:53 Here's a servo diagram for a 1998 850. As abscate said, there is one fewer servo in 1999- (because they combined two?).

Looks like your picture is the passenger's side temp damper motor (and the driver's side is identically diagonal on the other side of the center console, visible with the knee panel removed). My notes say that in 1999-, the floor/defrost motor was combined with the left vent damper motor. Since I don't see the right floor/defrost, is it possible that yours was combined in 1998? Regardless, I recall it being easy to pull the driver's knee panel and see the two dampers there.

My floor/defrost is broken in my 2000. VIDA stores codes showing that it's not working how it should. Doesn't help for 1998, but maybe the 850 scanner app could show similar info.

Mine is a 98 V70.
All the forum posts I read about the LED test and tapping into a ODBII plug under the coin tray do not match up to what I see on my car. My ODBII is under the center armrest. I'm trying to figure out how to see the error codes without going to my independent mechanic, which charges 1hr of diagnostic for just about anything at at cost of $175. It's criminal.

Of the two dampers on the driver side, do you know which controls the windshield / front vent direction?
Here's a screen capture of a YouTube video someone did for a 96 850 (

He's pointing at a damper closest to the front. It's not super clear from his commentary if that's the one I am after.

: Closer front damper.; CLoser Front damper.png (970.25 KiB) Viewed 360 times

Is this the one I am after? Or is it the one deeper in the dash?

When I have time, I'll check out the dampers at the driver side. Something for another day of tinkering.