Auto Climate depends on 3 sensors - Outside ambient (which shoild be ok), Solar/Sun ray sensor (this measures the intensity of the sun, sensor is by the windscreen heater vents (passenger side) and looks like a little black dome and you'll also have a cabin sensor which is by the left hand panel under the steering wheel (its like 2 or 3 slits in that panel) and depending how old the car, it could have got dusty, you will need to take that panel off and get to the sensor behind it and lightly vacuum it out as dust etc gets in there. if all else fails Solar/Sun ray sensor could be iffy.