1. Simple Checks:
* Check the fuse: Locate your Blazer's fuse box (usually under the hood or in the interior, often near the steering column). Consult your owner's manual to find the fuse for the fuel gauge. Check if it's blown and replace it if necessary with a fuse of the same amperage.
* Check the fuel sender unit: This is the most common culprit. The sender unit, located in the fuel tank, floats on the fuel and sends a signal to the gauge. A faulty sender unit can provide inaccurate readings or no reading at all. This often requires dropping the fuel tank to access it, a more involved repair.
* Check for loose connections: Inspect the wiring harness connections at the fuel gauge itself (usually in the instrument cluster), and at the fuel sender unit. Loose or corroded connections can interrupt the electrical signal.
2. Intermediate Checks:
* Test the fuel gauge: If you have a multimeter, you can test the fuel gauge directly for continuity and proper voltage. This requires some electrical knowledge. Consult a repair manual for your specific Blazer year and model to find the correct wiring diagram and testing procedures.
* Check the wiring: Visually inspect the wiring harness running from the fuel sender unit to the instrument cluster for any damage, breaks, or shorts. Repair or replace damaged wiring as needed.
3. Advanced Checks/Repairs (Likely Require a Mechanic):
* Replace the fuel sender unit: As mentioned before, this is a common cause and may require professional help due to the fuel tank's location and the need for careful handling of fuel.
* Instrument cluster repair or replacement: If the gauge itself is faulty, it may need repair or replacement. This is typically a more expensive option.
* Computer Module Issues (PCM): In some cases, a problem with the Powertrain Control Module (PCM) could be affecting the fuel gauge signal. This is a more complex diagnosis and repair.
Before you start:
* Consult your owner's manual: It contains specific information about your Blazer's fuse box location and diagrams.
* Safety First: Always disconnect the negative battery terminal before working on any electrical components, especially those near the fuel tank. Be cautious when working with gasoline.
* Professional help: If you're not comfortable working with automotive electrical systems or fuel tanks, it's best to take your Blazer to a qualified mechanic.
By systematically checking these points, you should be able to narrow down the cause of the malfunctioning fuel gauge. Remember to note the year and model of your Chevy Blazer as this significantly affects the specifics of troubleshooting and repair.
