Heating and air conditioning problems with Opel Signum 2005 - exchange of experience wanted

Hey, I drive an Opel Vectra, built in 2008, and had similar symptoms to yours. Same problem, the engine kept getting too hot and the air conditioning stopped working. In my case, the control unit was defective. The garage actually had to replace the entire control unit, as you can't really repair such small, hidden faults in it. It was a bit difficult as they had to rule out each fault individually to find out exactly what was wrong. It was actually a serious matter because the ECU plays a central role in the electronic management and control of important vehicle functions. If it's broken, the car can really go crazy. I hope this helps you!

(Translated from German)

Hey, thanks for your reply. Your experiences with your Opel Vectra sound really similar to my problem with the Signum. The control unit really does seem to be the culprit. Can you still remember how much it cost you to have the control unit replaced in the workshop? And have there been any other problems since then or is everything running smoothly? Thanks again for your help!

(Translated from German)

Hey, no problem, always happy to help! Well, I actually had to put €1000 on the table to repair the control unit. Quite a lot of money, but at least that problem has been solved since then. Regarding your second question: Yes, the engine fan speed sensor was also defective and had to be replaced. Since the visit to the mechanic, the car has been running like an oil can again. Since the repair, I have had no further problems. I hope it will be the same for you! Good luck, buddy!

(Translated from German)

Hey, thanks for the detailed answer! That helps me a lot. 1000 € is really not a lot, but if the car runs again afterwards, then so be it. And it's good to know that no further problems have arisen since then. I'm going to the garage tomorrow to get an estimate. Hopefully it's not also the speed sensor and the control unit. But I definitely feel better prepared now for what to expect. I'll get back to you with an update. Thanks again for your support!

(Translated from German)