1991 Chevy Cheyenne 4x4 fuse
I have a 1991 Chevy Cheyenne 4x4 pickup. Every time a new fuse is put in for the 4x4 it blows. You do not have to
engage the 4x4 for this to happen. I have traced the wires and found nothing wrong with them. I tried just putting a wire
from the 4x4 to the fuse box but it gets really hot.
Check the amperage going to the fuse
I doubt you have a meter that can test the amperage without piping the very expensive internal fuse on the meter. There is definitely a short somewhere. An old trick to find it is to go to the junkyard and get about 20-30 of the correct size fuses or a circuit breaker. Get a wiring diagram and find out what that fuse controls. I'm guessing it goes from the fuse to the switch and possibly branches and also feeds a relay. Unplug everything on that circuit and put the fuse in. If it pops then its somewhere right after the fuse, if its good then plug stuff in one thing at a time working your way away from the fuse. Probably starting with the switch itself. When it pops then you know there is an issue between the item just plugged in and the previous item. If you get to the control motor and it pops then its something internally shorting and you will need a new control motor. If you know how to trace wires then you seem like you should be able to handle this no problem. If you need me to be more descriptive I can get a pic on here for you of a simple wiring diagram.
Wire a light bulb between the contacts of the fuse terminals, works awesome as a checker for shorts. When the light goes out you found the short. It will shine if there is one. Since it's a load it doesnt fry anything, just uses the voltage.
John< the fuse is for the 4x4.
Ok but does the fuse operate the switch, the motor itself, relays one thing or multiple? I'm positive its more than just 1 wire coming from that fuse feeding only 1 thing. If you are unsure as to how to do what Andrew and I have explained then you will have to pay someone to do it.
It only says 4wd under the fuse. I think I will have to take it somewhere. I really do appreciate the help you have given.
The 4wd fuse supplies power to the TCCM and anything related to the 4x4 system and sensors.
Lol 2 sentences in one up there. "I'm positive its more than just 1 wire coming from that fuse feeding only 1 thing." That was supposed to say I'm positive there's more than just 1 wire coming from that fuse. There's no way it's feeding only 1 thing. Oops mind was moving faster than my fingers. To make it simpler, think about how many items in your vehicle require electricity. Imagine having an individual fuse for everything. They save space, money, and weight by using a single fuse for many different things. Anyways, I wish we could have helped more, if you decide to attempt to go at it just make sure if you decide to use the light you need to use proper sized spades so you don't stretch out the fuse contacts. Good luck
Lol, i took a blown fuse, cut into one side of the contacts and soldered the wires into each exposed contacts. It works awesome.
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