How to Test a Car Fuse Box for a Current

by Bob White

An automobile typically has two fuse boxes. One, located in the engine compartment, is for the motor's electrical needs, and one in the cab of the vehicle is for accessories and lights. The fuses protect each circuit from excessive amps, which may damage the components. Troubleshooting an electrical short requires tracking down the bad connection through trial and error. One place to check is at the connections in the fuse boxes, using a 12-volt test light.

1

Open the panel on the front of the fuse box by prying back its latch with your hand.

2

Turn the vehicle's ignition to the "power on" position without starting the engine.

3

Secure the 12-volt test light's alligator clip to any bare metal near the fuse box. A bolt is a good location.

4

Touch the bare metal on top of each fuse with the test light's probe. If the 12-volt test light illuminates, there is current at that connection.

5

Touch the bare metal inside each fuse holder if you are looking for a spare fuse location that has a current.

Items you will need

About the Author

Bob White began his writing career in 2006. Working in sales, he was a technical writer tasked with responding to requests for proposal. White has a Bachelor of Arts in computer science and a diploma in home inspection. He has also worked in construction, landscaping and the pool industry for more than 15 years.

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