Renault Master Temperature Sensor Issues

I also drive a Master. Your problems sound familiar! I had similar issues with the AC and mirror heating. It turned out to be a faulty outside temperature sensor. Did you check the wiring and connections to the sensor? That's where my problem was – a corroded connector. Is the sensor itself giving any readings at all?

I checked the wiring and connections, but perhaps not thoroughly enough. When you say corroded connector, was it visibly corroded, or did you need a multimeter? Also, do you mean the vehicle temperature gauge when you say 'readings'? I don't have diagnostic tools. Before replacing the sensor, is there any way to calibrate it?

It was visibly corroded, a bit green. I didn't use a multimeter. Electrics aren't my strong point. As for calibration, I'm not sure. I wouldn't mess with it too much yourself, or you might break something. I'd recommend taking it to a workshop. They can properly diagnose it and give you a fixed price.

I took it to a workshop, and you were spot on – it was a corroded connector! They cleaned it and replaced a short section of the wiring, and everything is working again. The total cost was 95€, which is much better than replacing the sensor. I appreciate your help!