"Does anyone have any ideas that make sense."
I'm going to choose to assume the last comment was not directed at my previous suggestion. You did not mention replacing the sensor.
"If you unhoon the sensor and use a paperclip to short the wires together in the terminal and the fans run constantly the cars runs OK. When you hook the sensor back up the engine dies.
I am thinking a short in the yellow wire from the ECM to the CTS (Coolant Temp Sensor)."
A "short" means the signal has an alternate path to ground. It should be easy enough test that theory with a mutlimeter or continuity checker.
If, when you short the sensor connector terminals the engine runs properly, it would suggest the output signal to the ECM is OK. I don't know which is the "yellow" wire, but as I recall it is at least a three wire sensor which suggests it requires external power in addition to the output connections. Is there power to the sensor when the ignition is on? Do you have access to a wiring schematic for the sensor? Even "brand-new" sensors have been know to be defective. I'm don't have access to my Lumina manual right now so I can't check myself.
Thursday, November 27th, 2008 AT 10:28 AM