Engine Coolant Temperature Sensor: Removal

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 Chevrolet Tahoe, 2003 Chevrolet Suburban, and 2003 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

Turn ignition off. Disconnect negative battery cable. Drain coolant below level of Engine Coolant Temperature (ECT) sensor into a suitable container. Disconnect ECT sensor harness connector.
On 4.8L, 5.3L and 6.0L models, ECT sensor is located on left side of engine, near front of exhaust manifold. See Fig 1.
On 8.1L models, ECT sensor is located on right side of engine, near middle of cylinder head. See Fig 2. On all models, remove ECT sensor.

Fig 1: Locating IAC Valve, EVAP Canister Purge Solenoid, MAP Sensor, ECT Sensor & TP Sensor (4.8L, 5.3L & 6.0L)

Courtesy of GENERAL MOTORS CORP.

Fig 2: Locating ECT Sensor, MAP Sensor & TAC Motor (8.1L)

Courtesy of GENERAL MOTORS CORP.