Automatic Climate Control Problems? Try This!!

Help, Advice and DIY Tutorials on Volvo's extremely popular car line -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.
1992 - 1997 850, 850 R, 850 T5-R, 850 T5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70
phat78ta
Posts: 280
Joined: Fri Jan 22, 2010 4:09 am
Year and Model: 94 850 turbo wagon
Location: ohio

Automatic Climate Control Problems? Try This!!

Postby phat78ta » Thu Feb 18, 2010 11:47 pm

I will begin by saying that Volvo makes an awesome car.
I recently started having issues with my ECC unit. The dreaded flashing lights. So I pulled codes, and found lots of issues, the temp fan, the blower motor, damper motor and others. I thought that the ECC control unit had given up the ghost. After looking into it, I found the temp sensor was working correctly, and the blower motor was woking properly also. Upon looking into the damper motor, I found that it was not working.
So, like any good do it yourselfer, I took the damper motor apart. I figured if it's broken, I can't break it anymore. Upon opening the housing, I found the circuit board covered in white grease. I cleaned some of it off before this pic:
Image
The black half circles were covered in grease also. I cleaned it off, and plugged it back in. all the codes went away, and the motor operated normally.
These contacts touch the black half circles:
Image
The grease is from the gears in the reduction system, and must have gotten on the contacts over the years.
Put everything back together, and all is well.
So, If you get the dreaded flashing lights, this is one more place to check before replacing parts.
93 850 GLT sedan 156K
94 850 Turbo 189K

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matthew1
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Re: Automatic Climate Control Problems? Try This!!

Postby matthew1 » Fri Feb 19, 2010 2:00 am

Good work! Entered into the Repair Database.
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1997 850 T5, MBC, injectors, R bumper, strut brace, dying paint
2004 V70 R [gone]

FCPGroton
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Year and Model: 2004 S60R
Location: Old Saybrook, CT

Re: Automatic Climate Control Problems? Try This!!

Postby FCPGroton » Fri Feb 19, 2010 2:33 am

Awesome find. I never thought to pull one of the motors apart to see if they could be fixed. I just assumed that when they go, they go.
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phat78ta
Posts: 280
Joined: Fri Jan 22, 2010 4:09 am
Year and Model: 94 850 turbo wagon
Location: ohio

Re: Automatic Climate Control Problems? Try This!!

Postby phat78ta » Fri Feb 19, 2010 10:14 pm

I thought the same thing too, so that's why I tore it apart. Kind of a silly design to make a critical contact that way, but maybe it has something to do with the position of the gear.
93 850 GLT sedan 156K
94 850 Turbo 189K

JDS60R
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Re: Automatic Climate Control Problems? Try This!!

Postby JDS60R » Sat Feb 20, 2010 4:56 am

While you are in there you can clean the contacts with a pencil eraser (go lightly) . Leave the half circles alone . If you wish to replace the grease use any silicone grease like syl -glide or any dilectric compound. The placement of the grease is to keep the electricity from jumping from one circle to another.

Great job on the write up
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OUS
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Joined: Sun Feb 22, 2009 2:02 am
Year and Model: 850 turbo wagon 1995
Location: Kansas City, MO

Re: Automatic Climate Control Problems? Try This!!

Postby OUS » Sun Jun 06, 2010 12:25 am

Where and what is the damper motor?

Darksidechris
Posts: 1
Joined: Thu Jun 24, 2010 7:55 pm
Year and Model: V70 1997
Location: Wales GB

Re: Automatic Climate Control Problems? Try This!!

Postby Darksidechris » Thu Jun 24, 2010 7:59 pm

Hi all,
I would also like to know where the damper motor is as I have problems with my climate control and want to try this fix before replacing anything expensive.

Thanks for an amazing site and forums, I've read loads of very helpful stuff and excellent how-to guides.

Chris.

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nightc1
Posts: 93
Joined: Tue Sep 01, 2009 1:54 pm
Year and Model: 99'V70 Base 140K+Mi
Location: Alabama, USA

Re: Automatic Climate Control Problems? Try This!!

Postby nightc1 » Thu Jun 24, 2010 8:52 pm

Darksidechris wrote:Hi all,
I would also like to know where the damper motor is as I have problems with my climate control and want to try this fix before replacing anything expensive.

Thanks for an amazing site and forums, I've read loads of very helpful stuff and excellent how-to guides.

Chris.


It's behind the glove compartment and the lower dash panel on the passenger side.

Here's a thread with schematic pictures so you can see where it connects to the guts under there...
viewtopic.php?f=1&t=27974&p=123684

As for what it is... it's the thing that directs which ducts the air is going to go in the airconditioning/heating system.

V850B5254T
Posts: 52
Joined: Sat Oct 03, 2009 5:09 pm
Year and Model: 2007 V70T aut
Location: Denmark
Flag: Denmark

Re: Automatic Climate Control Problems? Try This!!

Postby V850B5254T » Mon Oct 18, 2010 7:13 am

The use of silicone grease or oil in any electromechanical devices like potentiometers (as here) or relays is questionable.
Most silicone based products will produce Silicium Oxide (SiO2) if exposed to a spark and SiO2 is an excellent isolator.
When the wiper in the pictured example slides over the resistor half circle it will produce small sparks, not visible to the eye.

I would use a calcium stearate based grease or siilar like Luberex from GC for the potentiometer.
Silicone and electromechanical parts just does't mix.

oakey
Now:
Volvo 850T stc 1996
Volvo 940T stc 1998

Before:
Volvo 850 stc 1994
Volvo 240 stc 1988
Volvo 240 van 1981
Ford Granada Van 1973
Renault 4L 1969
VW T2 1970
Morris Mascot 1970
Renault 4L 1962

V850B5254T
Posts: 52
Joined: Sat Oct 03, 2009 5:09 pm
Year and Model: 2007 V70T aut
Location: Denmark
Flag: Denmark

Re: Automatic Climate Control Problems? Try This!!

Postby V850B5254T » Mon Oct 18, 2010 7:24 am

The grease shown in the picture was used to protect the plastic cog wheels from wear. It is possible that the grease has entered the potentiometer and caused your problem. However, it is more possible that scrapings from the half circle resistor on the PCB has clogged the connection between wiper and resistor.
Never use silicone products for electro mechanical parts.
I would use a calcium stearate based grease or similar like Luberex from GC for the potentiometer.
HAM radio homepages has a lot of information about how to handle and repair electronics.

oakey
Now:
Volvo 850T stc 1996
Volvo 940T stc 1998

Before:
Volvo 850 stc 1994
Volvo 240 stc 1988
Volvo 240 van 1981
Ford Granada Van 1973
Renault 4L 1969
VW T2 1970
Morris Mascot 1970
Renault 4L 1962


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