Hot and Cold Air

[EVOeng]

Afternoon,

Hoping I can get some help from the nice chaps on here.
I recently purchased a 05 (Facelift) Volvo V70 2.4 (170) Auto (if it makes any difference), and am having a slight problem.

Upon start up, and a further 5 minute journey the car warms up as normal, however during this time the heater blows cold air out, then warm, then cold (every few seconds) until the car is up to temperature. This means that every few seconds you are either extremely cold or nice and warm. As I said, once the car is up to the correct temperature, it blows heat at the right temperature, constantly.

Thanks in advance,

Ram

[Georgeandkira]

Hello, Is it a manually controlled A/C unit or an ACC? I assume it's an ACC. Can you override this crazy temperature swing with the controls? I'm wondering if the blend door is going through some kind of test circuit. Do a search and see if there are any postings on "resetting" an ACC unit. Saabs have them-a simultaneous pushing of 2 buttons starts a check and reset. Errors are read out. MAYBE an '05 Volvo has a similar feature. That everything comes to rest eventually makes me think nothing physical is broken. Kira

[rogerb]

Hi,
It may be worth checking the water level is not low, although you should get a dash light/warning.
On my V70 the temp would not be right some times
I moved the setting knobs to full cold pause 10 seconds
and then to full hot, and repeted this 5 times. This seames to have cured my cars problem.
I did look on vida/dice and you can read out the position of the motor position sensors to see what
is gooing on, as well as a calibration set up routine, if you need it, althtough I have not done my car
as it is fine now that I excised the motors to each end of there movement.
It may be worth a go on your car.

Regards Rogerb

[Webby]

I have the same problem in my 05 S80. It blows hot then cold constantly. The car eventually warms up but it still alternates between the two.

I will do a search on the forum for resetting the ACC, but it is very strange.

[sneakypenguin]

Sounds like the blend door is confused. As suggested try doing a reset. It may also be the switches/rehostats had a bit of dirt on the contacts. Try moving from cold to hot repeatedly for a minute on each one, that should eliminate any dirt on the contacts.

Hth

mike

[EVOeng]

Many thanks chaps, I will try and find out how to reset the ACC.

[EVOeng]

I don't suppose any of you kind chaps know how to reset the ACC?

[Georgeandkira]

Hello, I found this. I haven't looked at it myself.

http://www.volvospeed.com/maintence.htm

I'll look for other stuff.

and this...http://www.brickboard.com/AWD/volvo/...unctionor.html

Kira

[EVOeng]

Thanks for the links, the second link looks interesting but finding the procedure is proving quite difficult.

[khile]

mines started doing this pulsing between hot and cold any info on resetting acc would be greatly appreciated