960 Aircon heating won't turn off

grahamdaldry · Post by **grahamdaldry** » 25 Jan 2017, 07:11

I have a problem with my 1996 960CD which has EEC. I can't turn the heating off. The aircon unit has the flashing blue light indicating a serious fault. The blower fan works fine (and can be switched off) but the heating is always full on hot, once the engine has warmed up. I have cleaning the cabin heat sensor in the light dome. The aircon has been re-gassed and there is an issue with the compressor leaking, but this is a separate problem I think. The diagnostic is giving 1-1-1 (no issues) or no reading at all. I imagine that either a valve is stuck, or the EEC unit has a circuit board issue. But any further or better thoughts on this much appreciated. If its the EEC unit, is there a simple way to test this?

lummert · Post by **lummert** » 25 Jan 2017, 14:32

Research ECC solenoid valve.

mydamnvolvo · Post by **mydamnvolvo** » 26 Jan 2017, 22:15

Set them all to auto and then 72. May be an input issue

lummert · Post by **lummert** » 27 Jan 2017, 14:51

On my 1988 760 Turbo Wagon with ECC I have to set the temp knob to it's highest setting to get heat. Anything lower and the heater blows cold air.

93Regina · Post by **93Regina** » 27 Jan 2017, 20:15

grahamdaldry wrote:I can't turn the heating off

Play with item 5

lummert · Post by **lummert** » 28 Jan 2017, 11:14

The heater control valve is open until closed by a vacuum source.