Load Cell Troubleshooting: 12 Common Problems and How to Fix Them

Load cells are essential components in weighing and force-measurement systems, but problems with the sensor, wiring, mounting, or surrounding equipment can lead to inaccurate, unstable, or inconsistent measurements. A load cell may be functioning correctly while an installation or electrical issue elsewhere in the system causes incorrect readings.

Common symptoms can provide useful clues when troubleshooting a weighing system. These may include a load cell not working, unstable readings, negative readings, zero drift, failure to return to zero, excessive electrical noise, or incorrect and non-linear output.

Before Troubleshooting a Load Cell

Before testing the load cell itself, inspect the mechanical installation, wiring, and surrounding equipment. Many weighing problems are caused by installation or connection issues rather than a failed sensor.

Safety and Inspection First

Begin by making the system safe and, where practical, remove unnecessary load before inspection. Avoid working on a loaded structure unless the equipment and procedure specifically allow it.

Inspect the load cell and its surrounding installation for:

• Damaged cables, connectors, or junction boxes
• Visible cracks, deformation, corrosion, or other mechanical damage
• Moisture, dirt, or contamination around electrical connections
• Crushed, stretched, cut, or pinched cables
• Loose mounting hardware or signs of mechanical movement
• Incorrect installation, alignment, or unwanted contact

Confirm that the load cell is installed according to the manufacturer’s specifications, including load direction, mounting arrangement, restraints, and clearances.

Check the Load Cell Wiring

Verify the wiring against the manufacturer’s wiring diagram before taking electrical measurements. Depending on the load-cell configuration, connections may include:

• Excitation + and − — supplies power to the strain-gauge bridge.
• Signal + and − — carries the measurement output from the bridge.
• Sense wires — used on many 6-wire load cells to compensate for voltage drop in longer cable runs.
• Shield/ground — used where specified to reduce electrical interference.

Incorrect wiring or reversed signal polarity can produce negative, abnormal, or inconsistent readings. A negative reading does not automatically mean the load cell is defective; the signal polarity, load direction, indicator settings, and wiring should be checked first.

For detailed connection information, refer to the Load Cell Wiring Guide (LCS-06).

A systematic inspection of the mechanical and electrical installation should be completed before concluding that the load cell itself has failed.

12 Common Load Cell Problems and How to Fix Them

Load cell problems can originate from the sensor itself, but they are also commonly caused by wiring, mechanical installation, environmental conditions, or weighing electronics. Use the following troubleshooting steps to identify the likely cause before replacing the load cell.

1. Load Cell Is Not Working

Symptom

There is no usable output from the load cell, or the weighing indicator does not register a load.

Likely Causes

Common causes include a broken cable, incorrect wiring, missing excitation voltage, damaged strain gauges, or a failed load cell.

How to Test

First, check that the load cell is receiving the correct excitation voltage. Inspect the cable and connectors, check continuity where appropriate, and measure bridge resistance with a multimeter. Also verify that the indicator or amplifier is receiving the signal.

Fix

Correct any wiring problems and repair or replace damaged external cables where appropriate. If the internal bridge or sensing element has failed, the load cell will normally need to be replaced.

2. Load Cell Is Not Returning to Zero

Symptom

The reading remains above or below zero after the applied load has been removed.

Likely Causes

Possible causes include mechanical binding, side loading, overload, cable damage, zero drift, or an incorrect mounting arrangement.

How to Test

Remove the load and inspect the complete mechanical installation. Check for contact between the weighing structure and surrounding equipment, friction, restricted movement, and cable forces. Compare the unloaded output with the manufacturer’s specifications.

Fix

Remove unwanted mechanical forces and correct alignment or mounting problems. If the sensor remains within specification, recalibration may restore correct zero performance. A permanently shifted or damaged load cell may require replacement.

3. Load Cell Shows a Negative Reading

Symptom

The displayed weight decreases or moves in the negative direction when a load is applied.

Likely Causes

The most common causes are reversed signal polarity, incorrect excitation connections, indicator configuration, or load being applied in the wrong direction.

How to Test

Check the wiring against the manufacturer’s wiring diagram and verify signal polarity. Also check the indicator’s input configuration and confirm that the mechanical load is being applied in the intended direction.

Fix

Correct the wiring or indicator configuration as required. Ensure the load is applied according to the load cell’s specified measurement direction.

4. Load Cell Reading Is Drifting

Symptom

The displayed value slowly changes even though the applied load remains constant.

Likely Causes

Temperature changes, moisture ingress, damaged cables, mechanical stress, poor mounting, and sensor ageing can contribute to drift.

How to Test

Monitor the zero and loaded output over time. Inspect the cable, connectors, mounting arrangement, and surrounding environment. If possible, compare output changes with changes in temperature or environmental conditions.

Fix

Improve environmental protection and correct mechanical installation problems. Replace damaged cables or components and recalibrate where appropriate. If the sensor has developed permanent drift outside its specification, replacement may be necessary.

5. Load Cell Has an Unstable Reading

Symptom

The displayed weight constantly fluctuates even though the applied load appears unchanged.

Likely Causes

Electrical noise, loose connections, damaged cables, poor grounding, vibration, and an unstable mechanical structure are common causes.

How to Test

Inspect connectors and terminals and check cable routing, shielding, and grounding. Observe whether the fluctuations change when nearby motors, drives, or other electrical equipment are switched on or off. Also inspect the mechanical structure for vibration or movement.

Fix

Secure electrical connections, improve cable routing and shielding, and reduce mechanical vibration. Address electrical interference from nearby equipment and correct any unstable mounting.

6. Load Cell Output Is Too Low

Symptom

The load cell produces an output, but it is significantly lower than the expected value for the applied load.

Likely Causes

Possible causes include insufficient excitation voltage, incorrect load-cell capacity, mechanical restriction, damaged strain gauges, or a signal-conditioning problem.

How to Test

Measure the excitation voltage and check the load-cell output in mV/V where applicable. Apply a known reference load and compare the measured output with the manufacturer’s rated output and specifications.

Fix

Correct excitation or wiring problems and remove mechanical restrictions. Verify that the load cell has the appropriate capacity for the application. If the sensor output remains outside specification, it may need replacement.

7. Load Cell Output Is Too High

Symptom

The weighing system displays more weight than expected for a known applied load.

Likely Causes

Incorrect calibration, wrong indicator scaling, unsuitable load-cell capacity, mechanical overload, or signal-conditioning configuration can cause excessive readings.

How to Test

Apply a known test load and compare the displayed value with the reference value. Check the indicator’s scaling, calibration settings, excitation, load-cell capacity, and rated output.

Fix

Correct scaling and calibration settings where necessary. Verify that the selected load cell is suitable for the application and has not been subjected to an overload that could affect its performance.

8. Load Cell Has Excessive Noise

Symptom

The output shows rapid fluctuations, electrical interference, or a noisy signal that does not correspond to changes in the applied load.

Likely Causes

Common causes include electromagnetic interference, poor shielding, grounding problems, damaged cables, poor connections, and nearby motors or variable-frequency drives.

How to Test

Inspect signal cables and their routing. Check shielding and grounding according to the manufacturer’s recommendations. Observe whether the noise changes when potential electrical interference sources are switched on or off.

Fix

Separate load-cell signal cables from high-power and motor wiring. Improve shielding and grounding where appropriate, and repair damaged cables or poor connections.

9. Load Cell Fails the Multimeter Resistance Test

Symptom

The measured bridge resistance is open, shorted, or significantly different from the manufacturer’s specified value.

Likely Causes

Possible causes include a broken strain gauge, internal wiring failure, moisture damage, electrical overload, or damaged external cable connections.

How to Test a Load Cell With a Multimeter

Disconnect the load cell from the weighing system before testing. Set the multimeter to resistance and measure the excitation and signal circuits according to the manufacturer’s wiring diagram. Compare the readings with the load-cell datasheet.

Fix

If resistance is outside specification, first investigate the cable and connector condition. If the internal bridge is confirmed to be damaged, the load cell will generally need to be replaced.

10. Load Cell Shows Non-Linearity

Symptom

The output does not increase proportionally as the applied load increases.

Likely Causes

Mechanical installation problems, overload, incorrect calibration, damaged sensing elements, or uneven load distribution can cause non-linear behaviour.

How to Test

Apply several known loads across the measurement range and record the output at each point. Compare the measured results with the expected response specified by the manufacturer.

Fix

Correct mechanical installation and load-distribution problems first. Recalibrate the system if appropriate. If the load cell continues to show excessive non-linearity outside its specification, the sensor may have permanent damage and require replacement.

11. Load Cell Has Excessive Creep

Symptom

The displayed reading gradually changes while a constant load remains applied.

Likely Causes

Creep can be influenced by the load cell’s characteristics, temperature variation, mechanical stress, overloading, or installation problems.

How to Test

Apply a stable reference load and record the output over a defined period. Compare the change in output with the manufacturer’s creep specification and check for environmental or mechanical influences.

Fix

Check the mounting arrangement, load conditions, and temperature stability. Recalibrate where appropriate. If creep remains outside the specified limits, the load cell may need to be replaced.

12. Load Cell Has Completely Failed

Symptom

The load cell has no usable output, a severe permanent zero shift, or abnormal electrical measurements.

Likely Causes

Possible causes include overload, shock loading, water or chemical ingress, cable damage, lightning or electrical surge, and long-term mechanical fatigue.

How to Test

Start with a visual inspection and check the wiring and connectors. Measure excitation and output voltage and perform bridge-resistance tests where appropriate. Compare all results with the manufacturer’s specifications.

Fix

Repair external wiring or connectors where practical and retest the system. If the sensor remains within specification, recalibration may be appropriate. If the sensing element or internal bridge has suffered permanent damage, replace the load cell.

How to Test a Load Cell With a Multimeter

A multimeter can help identify common load-cell wiring, bridge-resistance, and output problems. Resistance tests can indicate open or damaged circuits, while a voltage test can help confirm whether the sensor is producing a usable signal under load.

Always compare measurements with the load-cell manufacturer’s specifications, because resistance and output values vary between models.

Step 1 — Disconnect the Load Cell

Before performing resistance measurements, isolate the load cell from the indicator, amplifier, transmitter, or data-acquisition system.

Do not measure resistance while the load cell is connected to powered equipment. Disconnect the sensor and make sure the circuit is de-energised before testing.

Step 2 — Identify the Wires

Use the manufacturer’s wiring diagram to identify the individual conductors. Depending on the load-cell design, these may include:

• Excitation + and − — supplies power to the Wheatstone bridge.
• Signal + and − — provides the measurement output.
• Sense + and − — used on many six-wire load cells to compensate for excitation-voltage drop.
• Shield — provides protection against electrical interference where applicable.

Wire colours are not universal, so do not assume a colour represents a particular function without checking the manufacturer’s documentation.

Step 3 — Measure Bridge Resistance

Set the multimeter to the appropriate resistance range and measure across the excitation pair. Then measure across the signal pair.

Compare both readings with the manufacturer’s specified bridge resistance. A reading that is open, shorted, or substantially different from the specified value can indicate a wiring, cable, or internal bridge problem.

Do not use a single universal resistance value as a pass/fail standard because load-cell designs differ.

Step 4 — Check for Shorts or Opens

Check the wiring for open circuits, unexpected low resistance, or short circuits. Inspect the cable and connectors carefully, as damage can occur near cable entries or connection points.

Where applicable, check for unexpected electrical continuity between conductors and the shield or load-cell body. The manufacturer’s specifications should determine what readings are acceptable.

Step 5 — Check the Load-Cell Output

After confirming the wiring and bridge resistance, the load cell can be tested for signal output under a controlled and safe load.

Connect the sensor to a suitable excitation source or approved test equipment and measure the millivolt output across the signal wires. Apply a known load and observe the change in output.

Load-cell sensitivity is commonly specified in mV/V. For example, a load cell rated at 2 mV/V with 10 V excitation would have an approximate full-scale output of 20 mV under its rated load.

Compare the measured output and response with the manufacturer’s specifications. The output should change consistently as the applied load changes.

When Should You Recalibrate, Repair or Replace a Load Cell?

Not every load-cell problem requires replacement. Wiring, mounting, connection, and calibration issues can often be corrected without replacing the sensor.

Recalibrate When

Recalibrate when the sensor is mechanically and electrically healthy, the output remains within specification, and the problem is related to calibration, scaling, or system setup.

Repair When

Repair external problems such as damaged cables, loose connections, or incorrect wiring. Retest the system after repair.

Replace When

Replace the load cell when there is abnormal bridge resistance, permanent mechanical damage, significantly incorrect output, severe overload damage, or internal environmental damage.

Frequently Asked Questions

How do you test a load cell with a multimeter?

A load cell can be checked with a multimeter by testing bridge resistance, continuity, and electrical output. First, disconnect the load cell from the indicator or amplifier. Measure resistance across the excitation and signal pairs and compare the readings with the manufacturer’s specifications. Check the cable and connections for open circuits or unexpected shorts. For an output check, apply a known load and measure the millivolt signal, then compare it with the rated mV/V output. Resistance values and wiring arrangements vary by model, so always use the manufacturer’s datasheet.

Why is my load cell reading drifting?

Load cell drift can be caused by temperature changes, moisture, mechanical stress, cable damage, poor installation, or sensor ageing. Check whether the mounting structure is stable and free from side loads or binding. Inspect cables, connectors, and junction boxes for moisture or damage. If the reading changes with temperature or remains unstable after mechanical and electrical issues are corrected, the load cell may require further testing or replacement.

Why won’t my load cell return to zero?

A load cell may fail to return to zero because of side loading, mechanical binding, overload, damaged cables, zero drift, or calibration problems. Remove the load and check that the load cell and surrounding structure can move as intended without friction or interference. Inspect the mounting, cable routing, and electrical connections. If the zero shift remains after correcting these issues, compare the unloaded output with the manufacturer’s specifications and recalibrate or replace the sensor if necessary.

Can a load cell go bad?

Yes. A load cell can fail due to overload, mechanical shock, moisture, corrosion, electrical damage, or long-term fatigue. Permanent damage may result in abnormal resistance readings, severe zero shift, unstable output, or incorrect measurements. Before replacing the sensor, check the wiring, connections, mounting, and excitation supply to rule out external causes.

Final Takeaway

Troubleshoot load cell problems systematically instead of replacing the sensor immediately. Start with wiring and connections, then check mechanical installation, electrical performance, and calibration.

Use a multimeter to identify common electrical faults and always compare readings with the manufacturer’s specifications, as values vary between models. Recalibrate when the sensor is functioning correctly but the system needs adjustment. If testing confirms permanent damage from overload, moisture, shock, or electrical failure, replace the load cell.