It’s my biggest riddle of all times! In November 2011 I’m getting my 94′ Volvo 850 T5, it’s driving great and is sure to get me to Munich from Stuttgart. Only the temperature (at -3°C outside temperature) turns over half of the display when the turbo is cold running. I already thought, said a friend, that it is normal after further distances that it turns up a bit. 3 days later the engine control light lights up – so I read something with you and switch to advised Lamdasonde and OT – dealer. The sign stays out for 1n week, also the fuel consumption adjusts itself from 14l to an average of only 12 liters of temperature increase but remains. Then we have bridged the fan relay, the fan engine works perfectly and jumps immediately. So I drive to Volvo to read out so much – result: Fan relays – changed – Fans still don’t start – again to Volvo – AHA ! Control unit. New control unit for 1050,- Euron ordered everywhere – but not jumps to the fan again – there is either a fan switch?