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2001 Spyder GT
634 Posts
I'd start with getting your fans to run properly. When you turn on the AC, the passenger side fan should come on even with a cold engine. With the AC off, the fans will come on when the engine coolant temp reaches 230°F. If you disconnect the ECM engine coolant sensor wire connector (there's two; you want the larger one with three wires instead of two) near the thermostat, the fans should come on immediately. That's an easy way to check whether the problem is lack of power to the fans, or a problem with the temperature sensor itself.

If you can't find the connector or if you discconect the sensor and the fans don't run, start by checking fusible link #2 and fuse #9 (20A) under the hood. Then test your fan control relay A-09X with a multimeter. After the relay, the next component is the fan controller, mounted to the driver's side fan.

The other thing to check is the engine coolant temperature sensor itself. If there's a problem with the sensor, the ECM might think the engine is always cold, even when it's hot, and never turn on the fans. A good way to check it is to connect an OBD reader, and compare the engine coolant temperature reported by the OBD against the gauge in the cockpit. They're separate systems so you can compare them and they should be in the same ballpark.

Now, you said your car overheats quickly so it's possible that you have a mechanical problem as well, like low coolant, a sticky thermostat, blown head gasket, etc. So there may be more to do once you get the fans working correctly.
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