How to test vehicle electrical fuses with a test light.
Using a test light(1) connected to a GOOD ground, probe both sides of the fuse. Key must be on. It is a good idea to check all fuses in all fuse blocks when a blown fuse is suspected. Some of todays vehicles use many fuses and several fuse blocks to power a particular circuit / system.
The fuse is the most common method of an automotive wiring circuit protection. Whenever there is an excessive amount of current flowing through a circuit the fusible element will melt and create an open or incomplete circuit. Fuses are a one time protection device and must be replaced each time the circuit is overloaded.
How To Check Fuses

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