W 150 Pickup V6-239 3.9L (1991)
Fuse: Testing and Inspection
To test the fuse, connect the negative lead of a voltmeter to a known good ground, and touch the positive lead to one terminal of the fuse. If battery
voltage is present, test the other terminal of the fuse. If battery voltage is present on only one terminal, then the fuse is defective. If battery voltage is
present on neither terminal, check for a burned fusible link or power lead wire to the fuse block.
