Frequently Asked Questions About Freightliner FLC120 Fuel Tank Senders

Will these fuel tank senders fit my specific year FLC120, and are they compatible with both single and dual tank setups?

Our fuel tank senders are designed to fit Freightliner FLC120 models from 1989 through 2003. They work with both single and dual tank configurations. However, the sender arm length varies based on your tank size (typically 11", 15", or 19" depths). Before ordering, measure from the top of your tank to the bottom to ensure you select the correct arm length. Dual tank setups will require two senders if you're replacing both.

What's the difference between a 0-90 ohm and 240-33 ohm sender, and how do I know which one I need?

The ohm range must match your fuel gauge specifications. Most FLC120 models from 1989-1996 use 0-90 ohm senders, while 1997-2003 models typically use 240-33 ohm units. You can verify this by checking the back of your fuel gauge for specifications or testing your existing sender with a multimeter. Using the wrong ohm range will cause inaccurate fuel readings or gauge failure.

How difficult is the installation, and what tools will I need?

Installation typically takes 1-2 hours per tank. You'll need a brass drift punch and hammer (never use steel tools due to spark risk), a new tank gasket, and basic hand tools. The main challenges are safely dropping the tank (which requires draining fuel first) and properly aligning the sender unit without damaging the float arm. Many customers recommend having a helper to support the tank during removal and installation.

Why does my new sender show inaccurate readings, and how can I fix it?

The most common causes are: bent float arms during installation, incorrect ohm range selection, or poor ground connections. First, verify the float arm moves freely through its full range without hitting the tank walls. Check all electrical connections, especially the ground wire - corroded grounds cause erratic readings. Some FLC120s require gauge calibration after sender replacement, which involves adjusting the empty and full settings on your dash gauge.

Are these senders made of corrosion-resistant materials, and what's the typical lifespan?

Quality fuel tank senders feature stainless steel float arms and chemical-resistant components to handle diesel fuel exposure. The sending unit housing should be sealed against moisture intrusion. With proper installation, expect 5-8 years of service, though this varies with fuel quality and contamination levels. Signs of failure include stuck readings, erratic gauge movement, or readings that don't match actual fuel levels. Regular fuel filter changes help extend sender life by reducing debris accumulation.