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From time to time, forum members ask for assistance in finding a parasitic load that is draining their battery, and the solution always involves pulling fuses in order to find the offender. The Cen-Tech Fuse Slot Measurement Tool (Harbor Freight / SKU 70079 / $20) makes this task faster and easier.
The tool comprises a digital ammeter and several fuse slot adapters for the most common sizes of wedge type fuses. Operation is simple – pull a fuse and place it in the tool’s slot, then using the correct size adapter, plug the tool’s cable into the fuse block location and switch on the tool. The display will show current drawn on that circuit up to 30 amps with 0.1 amp resolution. If the circuit measures a non-zero value, you’ve found the offender. Otherwise, replace the fuse and move on to the next one.
A very useful tool, especially for owners of older cars whose electrical wiring and components might be aging.
Great tip. That Harbor Freight tool is a lifesaver for tracking down battery drains. Makes the process much faster than pulling fuses one by one. Highly recommended for anyone dealing with parasitic draw.
2025 AMG G 63 SUV /// 2025 AMG GT 63 S E Performance 4 Door Coupé
Great tool and I apologize in advance for taking this a bit off topic.
Could an E-Fuse cause parasitic drain? With the newer E-Performance models blade fuses are becoming less of a thing because of all the complexity of the high voltage drivetrain.
A fuse shouldn't be causing a parasitic drain -- it protects the wiring and load on a circuit that could have a parasitic drain. This instrument is not for checking fuses, but for finding circuits drawing current when they shouldn't be. Not familiar with the term "E-fuse".
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