Question about 2007 Chevrolet Cobalt Coupe

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The coolant temp will sometimes go blank (---) and when it does the AC stops working. When the temp reads. Number the AC kicks back on. My check engine light is also on sometimes. I took it to autozone who told me that it said the coolant temp is too low or something like that. Which I can only assume is because it's not reading any temp at all.

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If your temp gauge is going blank several things can cause this. one is a bad wiring connection on the sending unit itself. could be corrosion on the connectors. these types of sending units work like a thermistat they do go bad. but id be looking for a loose ground. since this circuit is grounded to the body you could ground the system by using a set of jumper cables. use one side to ground the battery to the body and the other side to ground the motor to the body and see if it still happens.
a large amount of electrical issues are created by faulty grounds. i usually start by disconnecting the harness from the sending unit and inspecting it,if its not damaged. i would then reground the systems

Posted on Aug 31, 2010

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Not really a answer to the question more info on the problem I have a 08 cobalt with the same problem I replaced the coolant temp sensor and pigtail to it and still have the same problem I found out that if you disconnect the battery or reset the computer with a scanner it will work for some time never more then a day tho. It sounds to me like its a ecm problem.

Posted on Dec 21, 2016


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Allow the engine to heat up to make sure that it begins to flow.
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