Here's the proper approach:
1. Diagnose the problem: The CEL is a symptom, not the problem itself. You *must* find out what triggered the light. This is best done in one of two ways:
* OBD-II Scanner: Get a relatively inexpensive OBD-II scanner (available at most auto parts stores). Plug it into the OBD-II port (usually under the dashboard) and it will read the Diagnostic Trouble Codes (DTCs). These codes will tell you *what* the computer detected. Google the codes to understand their meaning.
* Mechanic: Take your Blazer to a qualified mechanic. They have the tools and experience to quickly diagnose the problem.
2. Fix the problem: Once you know the DTCs, you can address the underlying issue. This could range from something simple (loose gas cap) to something more complex (faulty sensor, emission system problem). Fix the problem, don't just reset the light.
3. Clear the codes (after repair): After you've repaired the issue causing the CEL, you can clear the codes. Many OBD-II scanners have a function to clear codes. Some auto parts stores will also clear codes for free if you bought a part from them.
Disconnecting the battery: While disconnecting the battery for a while *might* temporarily turn off the CEL, it won't actually fix the underlying problem. The light will likely come back on unless the problem is resolved.
In short: Focus on *fixing the problem* that triggered the Check Engine Light. The light itself is just an indicator that something needs attention. Resetting it without fixing the issue is a bad idea and could lead to more serious problems down the road.
