Posted by gmharris [71.105.40.248] on Saturday, June 01, 2013 at 18:29:59 :
In Reply to: Re: Very off topic posted by chris [71.48.171.71] on Saturday, June 01, 2013 at 09:35:36 :
By "immediately", I meant simultaneously with turning the AC switch off, indicating an electrical problem in the gauge, not an overheating problem.
You need to first make sure it is really an overheating problem. Is the engine showing signs of overheating? Get or borrow an infrared thermometer to verify what the temp gauge is saying.
Then, before taking it to a mechanic, go over the basics, as others have said. Check coolant level, belts, obstructed radiator, fan clutch, collapsed hose and possibly thermostat.
You say the temp returns to normal when the AC is in the low position. This makes me think that it may be an electrical problem. I assume you have a mechanical fan, but I don't know. A malfunctioning temp sensor could be a problem if you have an electric fan.
When I have a problem like this, I always google it. It's surprising how many people have had similar problems with a certain vehicle and have a solution for the problem.