Where is the temp gauge on a 2008 x5 3.0i - Cars & Trucks

have you checked the water in the radiator lately
probably overheated and the gauge is not working because there is no water to measure the temp in

have you had the coolant itself checked , may not have enough in system , this could stop the gauge registering as only reads hot water/coolant not hot air/steam

You have a water intrusion problem. The first step is to locate where the water is coming into car. The water is apparently getting in the wiring harness.

when a temp gauge drops to cold ,it indicates a problem in the cooling system
temp gauge sender units need water to activate the resistance that makes the gauge read so a falling gauge indicates no water around the sender unit --- air lock in the system--faulty wire connection to the gauge sender unit
the ac unit is not connected to the temp gauge so there may be another separate problem there
the temp sensor is an entirely different unit to the temp gauge sender unit and the short term working would be from an altered coolant level from changing that sensor --air lock in system
the temp sensor connects to the ECM to activate the fans and monitor engine operating temp so as to keep the air/fuel mixture exact for the engine conditions
the temp sender unit just makes the temp gauge read
a faulty thermostat will either be stuck open and the engine temp will take a long time to rise or it will be stuck closed and that will cause an overheat very quickly

old post and no symptoms, what reads wrong? or? scan fails or gauge? what?
for efi or the dash guage.? SAAB (2 "A"s?)
most newer cars is one sensor for both, FSM show this
as does alldata.com
ill answer for ECT.

2.0Liter. (google shows 500k hits but sure takes time to find it)
do you see the top rad hose, and it goes to the thermostat housing
and on said housing is the ECT.
this is for ECU usage. only. but ECU may repeat it to dash gauge.

On my 2008 Chevy pickup, the temp gauge would show normal temp and all if a sudden would drop out down to 160 on dash. When this happened, the panel would show ENGINE HOT, AC OFF. I had this problem for months. To reset it, I would have to pull over, take the battery cable off to reset the panel. I finally did some research and found out that the thermostat was the problem! When you replace the thermostat, make sure you get one that is set at 195 degrees cause there are different set points and if it doesn't make temp, the computer automatically takes over to prevent engine damage. I went to Autozone and bought a Failsafe 195 temp thermostat and my truck hasn't had a problem since!

Souds like it's way low on coolant. The heater will blow cold air when the cooling system is so low that there is no water (coolant) running through the heater core. Then the thermostat opens, it trys to be normal but the system is low so it gets too hot in just a few minutes. If its that low, there must be a leak somwhere.

It probably low on coolant. The heater will blow cold when there is not enough water (coolant) to keep the heater core full. Check the radiator (not the overflow reservoir) when it's cool.

Is it vacuum operated air diverter flaps or water valves? If so could be vaccuum leak. Listen for leaking air at the heater controls.

an air lock in the system.that is what the bleeders for...