Chevrolet Blazer Fuel Tank Selector Switch: A Complete Guide (1981-1989)
If your Blazer is struggling to switch between fuel tanks, this guide will help you diagnose and fix the problem.
- The dash switch and the frame-mounted selector valve are two separate parts; diagnose which is faulty before buying parts.
- Verify if your Blazer is carbureted or fuel-injected (TBI), as they use different switches.
- Symptoms like stalling after switching or being stuck on one tank are common signs of failure.
- ACDelco and Standard Ignition are top-tier aftermarket brands for this part.
Is Your Blazer's Fuel Selector Switch Failing?
A bad fuel tank selector switch can leave you stranded, even with a full tank of gas. The switch itself is a common failure point on these classic Blazers. The internal contacts wear out or get dirty, leading to a range of fuel-related headaches. Because this switch controls both the fuel valve and the gauge, a failure can be confusing. You might think you have a bad fuel pump or a clogged line when the real culprit is this small switch on your dash.
Symptoms of a Bad Fuel Tank Selector Switch
Keep an eye out for these common signs of a failing selector switch. Often, the problem isn't the switch itself but the selector valve on the frame rail. However, since the dash switch is easier and cheaper to replace, it's a good place to start.
- Engine Stalls After Switching Tanks: You press the button to switch from the right tank to the left, and the engine sputters and dies. This often means the switch failed to activate the selector valve or the other fuel pump.
- Stuck on One Tank: The truck runs fine on one tank, but refuses to switch to the other. You might press the button and nothing happens.
- Inaccurate or Dead Fuel Gauge: The switch might successfully change tanks, but the fuel gauge gets stuck on one tank's reading or shows empty for both. This happens because the switch is responsible for routing the signal from the correct sending unit.
- Fuel Transferring Between Tanks: If you notice one tank is overflowing while you're running on the other, it's a sign that the return fuel is being sent to the wrong tank. This is usually a problem with the selector valve, but can be related to the switch's signal.
Important: Carbureted vs. Fuel Injected (TBI)
Chevrolet switched from carburetors to Throttle Body Injection (TBI) around 1987. The fuel selector switches for these two systems are different and are not interchangeable. TBI switches have different internal wiring to control the in-tank fuel pumps. Always verify your Blazer's fuel system before ordering a new switch.
Choosing the Right Aftermarket Switch
For a vehicle of this age, the original GM part is likely discontinued. Aftermarket parts are your only option, but the quality is generally very good. Here’s a breakdown of the available brands.
Tier 1: OEM-Quality Brands
- ACDelco: Often considered the original equipment supplier for GM, ACDelco parts are designed to meet or exceed factory specifications. For electrical components, they are a trusted choice among mechanics and enthusiasts. While some production has moved overseas, they are still a top-tier option.
- Standard Ignition (SMP): Standard Motor Products is a highly respected aftermarket manufacturer with a long history. They produce reliable electrical components and are known for good quality control. Many professional mechanics use Standard parts without hesitation.
Tier 2: Quality Aftermarket Brands
- Rostra Powertrain: Rostra is a large manufacturer that produces a wide range of automotive electronics, including components for original equipment manufacturers. They are a solid choice and produce quality parts, though they may be less commonly seen in retail stores than ACDelco or Standard.
Tier 3: Economy Brands
- Replacement: This is often a house brand for various online retailers. These switches are designed to be a direct, low-cost replacement for the factory part. While they can be a budget-friendly solution, their long-term durability may not match the Tier 1 brands. They are a viable option if budget is your primary concern.
Pro Tip: Check the Selector Valve First
Many fuel switching problems are caused by the selector valve, not the dash switch. This valve is located on the frame rail. Before replacing the switch, have a friend press the button while you are near the valve. You should hear a click or a whirring sound as it actuates. If you hear nothing, test for 12-volt power at the valve's electrical connector when the switch is pressed. No power points to a bad switch or wiring; power but no action points to a bad valve.
Cost of a New Fuel Tank Selector Switch
| Part Type | Typical Cost |
|---|---|
| New Aftermarket Switch | $20 - $45 |
| Shop Labor for Installation | $50 - $100 |
Note: Costs are estimates and can vary based on brand, location, and vehicle condition.
Frequently Asked Questions
Can I drive with a bad fuel selector switch?
Yes, but with caution. If your Blazer is stuck on one tank that has fuel and runs properly, you can continue to drive. However, you will not be able to access the fuel in the other tank, effectively cutting your range in half. Avoid switching tanks until the part is replaced to prevent stalling.
How hard is it to replace the dash switch myself?
Replacing the dash switch is a very easy DIY job that usually takes less than 30 minutes. It typically involves carefully prying the switch out of the dashboard, unplugging the electrical connector, and plugging in the new switch. Be gentle, as the old plastic dashboard can be brittle.
Why does my fuel gauge read past full or not at all on one tank?
This is a classic symptom of a problem in the selector circuit. It could be the dash switch failing to change the gauge input, a bad ground at the fuel tank's sending unit, or a broken wire between the tank and the selector valve. The switch is responsible for telling the gauge which tank to read from.
I replaced the switch, but it still doesn't work. What now?
If a new switch doesn't solve the problem, the issue is likely elsewhere in the system. The most common culprits are a failed fuel tank selector valve on the frame, a bad in-tank fuel pump (on TBI models), a poor ground connection at the tank, or a break in the wiring between the switch and the valve.
Technical Specifications
OEM Part Numbers: 14028811
Dash-mounted rocker switch. 4-prong or 6-prong blade-type male terminal, depending on year and fuel system (Carbureted vs. TBI).
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
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- Is Your Blazer's Fuel Selector Switch Failing?
- Symptoms of a Bad Fuel Tank Selector Switch
- Important: Carbureted vs. Fuel Injected (TBI)
- Choosing the Right Aftermarket Switch
- Pro Tip: Check the Selector Valve First
- Cost of a New Fuel Tank Selector Switch
- Frequently Asked Questions
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