I have a 1995 F250 with Automatic Tranny and the 5.8L Engine. Fuse #5 in the Power Distribution Box blows as soon as I turn the key to the on position. According to the owners manual this fuse protects the Back-up Lamps, the Oxygen Sensor Heater, and the Trailer Battery Charge Relay. I'm assuming the Back-up Lamps aren't the problem because the fuse blows before I even put it in reverse. Where are these other 2 items located so I can check them out?
Thanks for any advice you can give me.
Vic

 

The oxygen sensor heater would be a good place to look, since it's mounted in the exhaust where the wires can get melted.

I think on your model you have just two. One on each side in or near where the exhaust manifold hooks to the downfall pipe. Some later trucks had a third oxygen sensor located down near the catalytic convertor. You might want to check there too.

Go over the wiring carefully, and it if looks good, but still blows the fuse, you could unplug each sensor to see if the problem went away.