Mercedes CLK diesel outside temperature sensor issue

I had a similar issue with my CLK. The symptoms sound familiar, especially the air conditioning refusing to kick in. Did you check the wiring harness near the front bumper? That's where the outside temperature sensor is usually located, and it's prone to damage from road debris and corrosion. It might be worth a look before you commit to a temperature sensor replacement.

Thanks for the tip. I will inspect the wiring harness. When you encountered this issue, did the vehicle temperature gauge on the dashboard display incorrect readings, or was it completely non-functional? Also, do you recall if you had to perform any sensor calibration after the sensor replacement, or was it plug and play?

On my car, the vehicle temperature gauge was showing drastically incorrect readings, something like -40 degrees Celsius when it was clearly not that cold! I didn't attempt a temperature sensor replacement myself. I took it to a workshop. The mechanic told me that there were no additional steps for sensor calibration after the sensor replacement on my car. I would still recommend checking it with a diagnostic device after the sensor replacement to make sure that everything is normal.

Your confirmation really helped solidify my suspicion. I inspected the wiring harness as you suggested and found a corroded connector. After cleaning the contact points, the issue was resolved. The air conditioning is now working, spray nozzles no longer freeze, and mirror heating is functional again. The vehicle temperature gauge is also displaying the correct temperature. I appreciate your assistance.