Hi guys,

I have a 2010 L1H1 2.3 diesel multijet panel van with climate control and bulkhead separating the rear.
In winter, once the engine warms up enough to heat the cabin, the interior temperature rises to an oppressive high and bakes me for between 10 and 30 minutes until, I assume, the cabin temp sensor kicks in and cools the cabin to my desired level. I prefer a coolish 18 or 19 degrees. The rest of the journey it works fine and the temp will rise or fall to whatever I set it to. It is a digital set up rather than a mechanical one. This happens on every journey when starting from cold.

Any suggestions gratefully received.

you may have a sticking blend door when it sits for a while it gets stuck then opens wide till it gets a signal to close may be worn dont know with how the climate control works on the fiat but i know the standard one does get stuck and cables stretch or fall from their keepers

Thanks for that.
I've never heard of a blend door as I'm just an idiot electrician but I'm sure that my mechanic friend who's about to service it will know exactly.

I'll get him to take a look.
Appreciate your help.

Automatic climate control isn't very intelligent.
When you start the engine the cabin temperature is way below what you want it to be, so the heater goes to full power but that doesn't do any good because the engine first has to warm up. The longer that takes, the more determined is the heater to reach the set temperature. And the system doesn't know it is trying to bake you because the sensor is tucked away somewhere with a lot of cold plastic near it.
Things will only improve if your mechanic friend can find the sensor and moves it to a location where it can react faster. Until then, set the temperature lower when you start and increase it after the engine produces sufficient heat.