1998 v70 Hot air through vents

Post by **chexny** » 10 Aug 2015, 07:00

I am getting extremely hot air coming through my vents when I have the A/C turned off and temp dials turned to cold. A/C works if turned on, this is just if I want to drive on a mild day say with the windows open. If I switch from outside air to recirculate then the hot air stops. Is that a t-stat issue that is stuck open? I changed it out a little while ago (18m ago?).

Post by **Homebrand** » 10 Aug 2015, 07:55

Are the controls for your heating/cooling controlled by cables?
I had this issue in another car (not a Volvo). It was the cables attached to the knobs behind the dash had broken their brackets. So in essence turning them would "pull" the hot on but when turned to cold it didn't adjust the "flaps". It simply went slack behind the facia.
Just a thought.

obayha · Post by **obayha** » 10 Aug 2015, 09:22

You probably have the ACC (Edit..ECC) and one or more motors to control the air flow are not working. Do you have flashing orange lights on your selector board on start up of car? I have one side blowing hot air and turn it off when I turn on A/C. Removing, repairing and or replacing these motors is not real easy. At least not so far for me. I hope to pull the dash on my parts car soon and learn about how all this works and maybe able to help others. There are some DIY's on here about cleaning the contacts on the motors and that may help the problem.
Shane

Post by **abscate** » 10 Aug 2015, 09:27

Just to complete the acronym soup here with the 'correct' Volvo terms

ECC is Electronic Climate Control (not the control unit, but the whole system -commonly misused)

If you have temperature numbers on your dash, I think this is the definitive test for ECC. The inputs from knobs are all electronic and are sent to the control unit which then activates motors to control the climate in your car.

MCC is Manual Climate Control - the knobs here pull/push cables which operate climate components

For OP, IM guessing you have ECC and your control unit is getting confused with your cold request and AC off button and is pushing air either through the heater core or ....it can be pretty hot under the hood too, especially if your car is a dark color!

obayha · Post by **obayha** » 10 Aug 2015, 10:05

Guess I was thinking basketball

Post by **chexny** » 10 Aug 2015, 10:28

Ha..the ACC response was throwing me off. I was trying to figure out if/how this was controlled through the ignition.

I have black/black and hot is an understatement.

I have ECC I believe.

Post by **abscate** » 10 Aug 2015, 11:29

Standard unit and Electronic Unit pictures

Post by **chexny** » 10 Aug 2015, 11:42

It is ECC - though I have different button types same configuration.

I do have orange flashing lights on start-up. I am not going into the dash to fix just this - I can just hit recirc button and it stops so not a huge deal. Was just wondering if this was somehow linked to the t-stat and sending coolant to the heater core when it I thought it should not be doing so.

Post by **abscate** » 10 Aug 2015, 11:44

Volvo heater cores always flow full. They are always hot. The ECC blends air from the either the AC or through the core to regulate temperature of the cabin.

Ill guess either the blend motor is acting up or could the hot air just be outside air from the hood area?

obayha · Post by **obayha** » 10 Aug 2015, 12:33

Could anyone post or point to a diagram of the motors and what functions they preform? Are they all the same motor?
Shane