Mechanics

FORD EXPEDITION FUSE PROBLEM

2002 Ford Expedition • 175,000 miles

Check engine light came on simultaneously with radio going out. Tried to replace fuse and blew again immediately. Code pulled says EVAP small leak/ no flow condition. Gas cap is good, no vacuum leak either. Is it possible a ground wire is loose that may be for radio and evap system sensor? If so where is it located?
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Guest
November 30, 2012.




A loose ground wire breaks the circuit which causes a reduction in current flow. Fuses blow because of too much current. The fault code is not related. It has to do with the evaporative emissions recovery system, not vacuum hoses. If there's a small leak, you usually need a smoke machine to inject a white smoke at 2 psi, then you look for where it's sneaking out.

A simple trick to finding a short is to replace the blown fuse with a pair of spade terminals, then use small jumper wires to connect them to a 12 volt light bulb. A brake light bulb works well. When the circuit is live and the short is present, the bulb will be full brightness and hot so be sure it's not laying on the carpet or against a plastic door panel. Now you can unplug electrical connectors and move things around to see what makes the short go away. When it does, the bulb will get dim or go out.

Caradiodoc
Nov 30, 2012.


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