How to Know if a Cluster Resistor Is Burnt or Good

Resistors provide resistance in electronic circuits to regulate voltage flow. As used in automotive cluster panels, the resistors provide voltage reduction for protection of the cluster panel lights from over-voltage and electrical spikes. All resistors have the possibility of becoming defective through normal wear from heat dissipation. When a cluster resistor fails, the lights on the cluster will cease to operate. Some resistors can provide visual clues that they are defective, but use of a digital multimeter can verify that the resistor is damaged.

Instructions

1

Orient the cluster circuit so that it is in full light, with the resistors facing upward.

2

Use a magnifying glass to look closely at the resistor in question. Look for signs of heat damage, which will appear as a burn on the surface of the cluster resistor, and possibly black carbon material near it on the instrument cluster circuit board. Any resistor with such dark spots should be tested with a multimeter, as it isn't always an indication that the resistor has failed.

3

Prepare your digital multimeter to test the desired resistor. Insert the plug of the black test probe into the jack labeld "COM" (common) or "GND" (ground). Insert the plug of the red test probe into the jack labeled "V/Ohms" (Volts and Ohms) and not the jack labeled "mA" as that jack is designed for measuring amperate in a circuit. Turn on the multimeter and rotate the needle on the dial so it is pointing in the "Ohms" section of the dial, and set it to measure Ohms at about the halfway mark to begin.

4

Touch the sharp tip of the black test probe to one of the wire legs on the cluster resistor and hold it in place. While holding the black test probe tip on the wire leg of one side, touch the sharp tip of the red test probe against the wire leg on the other side of the cluster resister. Look at the digital display on the multimeter and observe if there is any resistance reading. If the readout displays "1." with no trailing zeros, it could indicate that the resistor is bad.

5

Change the dial on the multimeter to measure the other resistance values and continue to check the resister. If the readout displays "1." with no trailing zeros regardless of which measurement denomination is selected, the resistor is "open" and cannot allow electricity to pass through. This resistor should be replaced. If the readout provides a numerical reading (such as 20.00) then the resistor is providing resistance. Consult with your automobile service center to find out what the exact reading should be for the resistor to verify it is providing the resistance necessary for the circuit.