[kandreasik]

So I have an issue that my car is letting all its coolant out, because the thermostat is not opening so pressure us building up. And I'm trying to figure out if there is a module that controls the thermostat that I could replace or reset and where it is located. I don't have any codes popping up, so that's why I think the thermostat is okay but the module controlling it isn't. I know my friend in one of his bmw 550 has an issue similar to this and it was the controller for the thermostat.
2004 range rover

 

[MARK_C]

The thermostat in a 2002 to 2005 BMW engined RR is no different than any other thermostat in any other car, except it has a electrical heater rod in it that the ECM can heat up to open the thermostat earlier than it would normally. The thermostat itself is just a regular wax pellet unit, where the wax in a bulb expands as the water gets hotter forcing the thermostat open. Replace the thermostat and if the thermostat is really the problem you will be good to go.