I have a 1991 4.0 V6 Ranger. The 40amp Fuse for the Fuse Panel keeps blowing in my truck. First of all what is a Fuse Panel Fuse, and secondly what keeps making it blow and what can I do about it. Every time it blows a little red light that looks like a battery shows up on the dash board on the inside of my truck.

 

Something on that circuit is pulling more amperage than the circuit was designed to handle, which is causing the weak link ( the fuse ) to burn up in order to protect the circuit the surrounding circuits the truck and its passengers.

Your Battery light comes on after the fuse blows to indicate the truck is no longer charging.

First thing I would do is disconnect the negative battery cable.( to keep your truck and you safe.).

Inspect the condition of your battery cables, terminal ends and battery. make sure to check both the positive and negative cables for corrosion ( clean or replace parts as needed )

If your battery is a sealed top battery and has been providing good cranking capability ( no weak or slow starter, or occasional need for a jump start ) just connect a DVOM and test the battery voltage with neither cable attached to the battery. Post your findings.

If the battery is low or has had cranking issues and you have removable cell covers inspect the fluid level it should at least cover the cells top off with distilled water as needed but do not overfill and try to recharge the battery.

Replace the battery if needed. If you are unsure bring it to a parts store for testing.

Then I would take a look at any aftermarket wiring or accessories Including any modifications to the truck that may have had alterations to the factory wiring.

If your truck has a aftermarket Audio system with a Amplifier or multiple amplifiers now is the time to say something about your system and or known modifications.

If your truck is stock you could and should obtain a factory service manual with a good wiring diagram and purchase a Short tester.





You may get lucky by just unplugging common items in that circuit that are known to fail like the alternator to find the short but it is best and most informative to find the short like the technician does in the video provided.

I will check in later to see if I can be more helpful.