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I only get heat on my S2 (non a/c) when I hit the defrost button. All sensors check out, flap motors working, solenoids working, heater valve working (but only on defrost) no vac leaks. Changed the ccu for a supposedly working one stll no joy. No broken clips. I'm stumped.
It started when temp controller needed turning hotter to get more heat and then no heat even on max when the mixer flap goes full cold and heater valve shuts. Is the new ccu faulty?
Sounds like it’s the heat/cold mix that’s the problem and that is a simple circuit. The motor (3) controls the heat/cold ratio by moving a lever that opens and closes a flap. So, it’s either not getting the correct signal from the control unit, levers/flaps are broken or stuck, or the motor is toast.
The temperature selector on the control unit is a common problem so I wouldn’t rule out your replacement unit having the same failure and therefore not sending the right signal to the motor.
Flap motor works but as you say it's not getting the signal from the temp controller. I have 3 ccus one has IC4 (the flap motor and heater valve IC) obviously burnt out, my original and a used (supposed to be working) one. Looks like I will have to bite the bullet and buy a new CCU
01-17-2018, 08:48 AM
Heater woes
