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coolant temp sensor

1716 Views 2 Replies 3 Participants Last post by  Chump
??? There's two wires coming off my coolant temp sensor. Anyone know exactly where these wires go to. 1991 Ramcharger with 360 motor.
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They go to the computer. This should be the sensor next to the bypass hose. There is another, smaller sensor with one wire coming off it on the other side of the a/c compressor, which goes to the gauge.

Matt {peace}
Tan and Black? Tan is the 5V reference signal from the computer and the black goes to a multiple Ground splice in the harness.

Description and Operation

The coolant temperature sensor is in the intake manifold next to the thermostat housing where it maintains constant contact with the engine coolant. The engine controller sends out a reference voltage of approximately five (5) volts to the coolant temperature sensor. As coolant temperature changes, the internal resistance of the sensor will change, causing a varying voltage drop across the sensor. The engine controller reads the voltage drop (input signal) across the sensor, and interprets this voltage drop as a specific coolant temperature. The higher the voltage drop the lower the actual coolant temperature and vice versa.

Based on the amount of voltage returning from the coolant sensor, the engine controller will:

Adjust the fuel injector pulse width. A cold engine will receive a longer pulse width, allowing for a richer mixture.
Monitor and adjust engine warm-up speed.
Adjust ignition timing when the engine is cold.
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