Temp gauge not working in my 2007 saturn Ion sadan. Some times it works but most of the time it does not. Because of that my AC also does not work.

Have the engine checked for proper operating temperature. NEVER listen to untrained parts counter persons.

How to Add Refrigerant to 2003 2007 Saturn Ion 1 2003 Saturn Ion 1 2 2L 4...

OK I am thinking that you may be low on coolant make sure the vehicle is cold and remove the radiator cap and make sure it is top full. then run the vehicle and add more if needed.

you might have a heater core issue also.

For the gauge, replace the thermostat. For the A/C it could be low on freon. Parts stores will put freon in for you. Use at least one can with dye in it. If it goes low again fast. A garage can find the leak.

Pretty common on these cars, its not light bulbs usually, they have LEDs, and most of the time the circuit board has gone bad. You might have some luck with this company

southernelectronics.com

There should be two sensors - one for the computer and one for the gauge. Are you working on the right one ? Can you ground the sensor plug and make the gauge move ?
Is the engine warming up ?

Hello,
Did you have a specific engine code requiring replacement of the Cam Position Sensor?
Did you recently replace the thermostat or run low on coolant or have some other cooling system work done? The temperature sensor can be bad, or simply have a loose wire connection. Check those. There can be air in the coolant system as well. Finally, the thermostat could be sticking and will need to be replaced.

These issues have nothing to do with the Air Conditioner. However, the AC will not cool if the car is sitting still unless the condenser fans (electric) are running. Turn on the AC and check to ensure the cooling fans energize.

Most of these items you can check yourself, however if not, then have your mechanic or a mechanically inclined family member or friend check them for you.

Best regards,

Does the clutch on the AC compressor operate the compressor when AC is called for? If no, check the fuse and relay for AC operation. If it does operate the compressor, then the system probably has a freon leak which must be repaired and the system recharged with freon. Replace the water temperature sensor if the radiator fan(s) do not come on when the engine is hot. The fan(s) should also come on immediately when AC is selected. Hope this helps!

It has a timing chain.

My 2007 Ion 2.2L sedan has the same issue. Every now and then when I am driving, the Cruise Control fails to engage. If I turn the car off, re-crank it, it works fine. Dealer cannot find the issue and it only happens about once a month. No bad computer codes or anything, just annoying.