Chosen Solution
The 2009 heatsink does not have a temperature connection? Is that normal? There is a spot for it on the logic board, but no wire from the heatsink.
The heatsink is incomplete the sensor has been removed, you need another one. The temperature sensor hangs just to the right of the fins on the copper bar.
Please indicate exactly which machine you have as the temperature sensors are different on different models. If you have a MacBook Core 2 Duo Santa Rosa/Penryn, there is only one temperature sensor.
Yes, this is normal. The 2009 white plastic non-Pro Macbooks don’t have their temperature sensors tacked onto the exhaust port of the heatsink, and so there’s no cable running from there to the logic board’s temperature sensor socket (J5520, to the left of the fan), but instead one temperature sensor is contained inside the CPU (the “CPU diode”), one is on the logic board in proximity to the CPU, one is inside the MCP chip, and one is on the logic board in proximity to the Northbridge chip that interfaces between the CPU and the rest of the logic board. A utility like Macs Fan Control can show you the temperature readings for all these sensors.
