How do you shut off the service engine soon light on 1999 blazer?

You can't just "shut off" the Service Engine Soon (SES) light on a 1999 Blazer; the light is an indicator that something is wrong with your vehicle's emissions system or another monitored system. Simply turning it off without addressing the underlying problem is dangerous and could lead to more serious (and expensive) damage down the road.

To properly address the SES light:

1. Get the diagnostic trouble codes (DTCs) read: This is the most crucial step. The SES light itself doesn't tell you *what* is wrong. You need a code reader (OBD-II scanner) to read the trouble codes stored in your Blazer's computer. Auto parts stores often offer free code reading services.

2. Identify the problem: Once you have the DTCs, you can look them up online (many free resources are available) or consult a repair manual to understand what the codes mean. This will pinpoint the potential issue, such as a faulty oxygen sensor, mass airflow sensor, or something else.

3. Repair the problem: Based on the DTCs and your research, you can either attempt to fix the problem yourself (if you have the mechanical skills and tools) or take your Blazer to a qualified mechanic for repair. Replacing the faulty sensor or component is usually the solution.

4. Clear the codes: *After* you've repaired the problem, use the code reader to clear the DTCs from the vehicle's computer. The SES light should then turn off. If it doesn't, there might still be an issue that needs attention.

WARNING: Simply unplugging the battery or using a code clearing tool *without* fixing the underlying problem will only temporarily turn off the light. The problem will likely remain and could worsen, potentially causing further damage to your vehicle. Ignoring the SES light is strongly discouraged.