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No defrost on a 2000 Base S70

Help, Advice and DIY Tutorials on Volvo's P80 platform cars -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, including 850 R, 850 T-5R, 850 T-5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

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leftyref56
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No defrost on a 2000 Base S70

Post by leftyref56 »

Please help. I have a base 2000 S70 with the ECC system. I get no light upon starting the car. My A/C works great. My heat works. My recirculate button also works, but everything come out of the dash vents. The center knob on the ECC unit does not redirect the airflow to the defrost or floor. I have pulled the dash pad and the glove box. I can see the recirculate motor behind the glove box a heater motor on the passenger side of the heater box. On the driver's side of care there is a motor right above the kick panel and one further up to the right of the instrument cluster. Which one controls the air direction and how do I repair it?
Thanks,
Bob H.

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bmdubya1198
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Post by bmdubya1198 »

Sounds like the damper motor arm is broken. There are a couple threads around here. If you look up behind the radio above the driver's side knee panel, you should be able to see the motor. Check to see if the arm is broken. If not, the motor is probably shot.
I'm not 100% sure that's the one for the defroster, but I'm pretty sure it is. Someone else will have to chine in.
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abscate
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Post by abscate »

I think I managed to salvage one from my 1999 base parts car if needed..I list the parts and numbers in my parts thread in the parts. For sale forum
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leftyref56
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Post by leftyref56 »

Thanks for your reply. i will pull the lower motor on the driver's side and see what I find.
Bob H.

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Post by scot850 »

Unfortunately you are too far ahead of me. Next week I plan to pull the whole dashboard from my 2000 V70 base to repair broken mounts. I'll be taking pictures and checking the system while I am in for function as I think the defrost is working but not completely.

Neil.
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leftyref56
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Post by leftyref56 »

Neil,
I will try to post pictures of my adventure. I am not in a great hurry to complete the same job as you, but I do want to get this done soon.
Bob

leftyref56
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Post by leftyref56 »

Sorry I haven't posted for a few days. Under the weather.

I pulled the dashboard and did repairs on it as the mounts were broken.

The motor that controls the dampers for the floor, vent and defroster is on the driver's side. I pulled the motor. It has a white cam that moves the air from the vents to the defroster. There is also a "v" shaped metal piece with tabs that fit into the cam and an arm that controls the air to the floor.

I pulled off the cam and fitted it in place and moved the flappers by hand. It turned easily and nothing was broken.

I put a nine volt battery to the motor to see if it would turn. It moved clockwise and counterclockwise as I switched polarity on the battery.

I hooked the motor back in the car and the 9 volt battery wouldn't move the motor in either direction.

Is the motor bad or do I have the cam in the wrong position?

i am about to put it all back together and buy an aftermarket defroster.

Bob
2000 Base S70

leftyref56
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Post by leftyref56 »

Position of Upper Motor
Position of Upper Motor
Cam on the upper motor
Cam on the upper motor

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Post by wizechatmgr »

When you first start the car are the lights by the AC and recirculation blinking? If they are, usually there is a fault it is sensing. It doesn't always blink them when it has a fault however.

I'd plug the motor into the car with it not seated in its normal position and see if the ECC is successfully able to move it. If so, then you have either an installation issue or something going on with the motor assembly internals.

If you can find someone with VIDA they can communicate with the ECC and you can see if it is sensing the position of the switch accurately at the ECC and if the motor is in the position the ECC attempted to move it to. You can also force it to do a calibration where I believe it does full sweeps on all the motors.
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leftyref56
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Post by leftyref56 »

I went to the Volvo dealership today and talked to a mechanic. he said the motor I have should be strong enough to move the vents. A nine volt battery is not strong enough to move the vents in the car. He said the ECC should reset when reattached. His suggestion was to put the motor back in hook up power and see if the motor moves.

The other suggestion was to manually put the dampers in the defrost position, put it all back together and see if it works. If nothing else I will have defrost until I wish to look further ( the ECC unit being bad or the motor not strong enough).

That is what I am going to do for now. I will still have heat but will also have defrost to get through the winter.
Thanks For the Help,
Bob

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