Simple and inexpensive way to diagnose if your electrical system has a short.
By: Wes Hepp

1) Disconnect your negative battery cable.

2) With your key in the “OFF” position, place a test light between the end of negative battery terminal and the negative post on your battery. (The test light should come on if you have a short that drains your battery while the truck is turned off).

3) Remove fuses from the fuse panel until the test light goes out. Once the light goes out then the circuit for the fuse you just removed will be the circuit that the short is located in. From that point you will know what wires you need to trace.