Where is the oxygen sensor wire at on a 89 Chevy 2500?

The location of the oxygen sensor wire on an 89 Chevy 2500 depends on which oxygen sensor you're looking for (there's usually one before and one after the catalytic converter) and the specific engine your truck has (a 6.2L, a 4.3L, or a diesel). There's no single universal answer.

To find it:

1. Identify your engine: Check your vehicle's documentation or the engine block itself to determine the engine size.

2. Locate the oxygen sensor(s): These are usually threaded into the exhaust manifold (pre-cat sensor) or the exhaust pipe after the catalytic converter (post-cat sensor). They're typically located near the engine but can be further down the exhaust system, depending on your engine and configuration. They look like small, cylindrical devices with a wire harness attached.

3. Trace the wire harness: Once you locate the sensor(s), follow the wire harness back towards the engine compartment. The wiring may be bundled with other wires, so carefully trace it to find the connection point. It will often lead to a connector near the engine control unit (ECU), or potentially a fuse box.

Important Considerations:

* Safety First: Always disconnect the negative battery terminal before working on your vehicle's electrical system. The exhaust system will be hot after running, so allow it to cool completely before attempting to locate the sensor.

* Repair Manual: A repair manual specific to your year, make, model, and engine is the best resource. It will provide detailed diagrams showing the exact location of the oxygen sensor(s) and their wiring. You can find these online or at auto parts stores.

Without knowing your specific engine, providing a more precise location is impossible. Use the steps above and consider investing in a repair manual for the most accurate information.