Fuse #15 Keeps Blowing

[buzzard73]

I have fuse #15 blowing out constantly...I hooked up a test light to the fuse block in this location...light pulses. I checked the voltage, it shows 11 volts down to 10...battery os perfect, brand new and fully charged. If I put a new fuse in it blows out in exactly 4 seconds each time. I figure there is a bad ground somewhere in the circuit...but not sure where. The red light on the dash blinks when I hook up the test light...turns steady after I disconnect the light...so power is constantly going to this fuse, low voltage but higher amperage. Totally confused and scratching my head.

1. Dash gauges don't work
2. Windows don't work
3. Stereo died (CD player went out first)
4. Interior lights don't work
5. Fuse #17 under the dash is fine
6. Disconnected alarm to see if that was the problem
7. no broken wires in the door looms (Checked all 5, and fixed some cracked wire covers in drivers door.)

 

[BigRondo]

Welcome aboard!!

The thread you posted in was almost 6 years old. I have taken your post and made a new thread in order to get better exposure.

Is it #15 under the hood in the Battery Junction Box or Fuse #15 under the dash in the Central Junction Box that keeps blowing?

 

[buzzard73]

Battery junction box. All other fuses under dash and in the battery junction are fine. It is a head scratcher for sure...lol...I checked the wires in the right front wheel well closer to the oil pan for damage, I checked the rear liftgate wires, next I will check the visor wires.

If anyone has an idea, please throw it out there, I am willing to check.

 

[BigRondo]

I can post up some stuff from my shop manuals tonight after work. Hopefully that will help you out.

 

[ExploreDeep]

Do you have an aftermarket headunit in this truck? You're correct about being grounded out. Pull out your dash and check all the wires first. If that doesn't work, pull out the gauges etc etc. It sucks but you'll see it instantly if its a bad enough short like you're saying. And please wear rubber gloves and have your battery disconnected when doing this. I've got the full zap a few times and it's not pleasant.

 

[buzzard73]

Pulled the factory head unit, checked door wires, disconnected and chased the alarm wires. Same problem.

Registers a parasitic draw of about 11 volts at .06 to 15.7 amps...pulses with about 3ohms of resistance...just enough to blow the fuse.

 

[ExploreDeep]

Try putting a taller fuse in and see what happens, I really don't know what else it could be

 

[buzzard73]

burns the bigger fuse.

 

[Lostcause66]

As an electrician I can tell you that all your going to get by putting in a bigger fuse is a car fire. The best way to find out what is causing the draw is to break the circuit down into sections until you find resistance. This can be done by following the harness from the fuse to what the fuse is protecting and unplug the connectors in between until you find the short. Definitely not fun. Your meter will show you exactly where the problem is. You should only have 1-2 ohms in between two points provided your meter is good, any more than that and you probably have a short or it's going to ground. I don't have the manual you need but there are guys on here that have shop manuals that will give you the wire colors for every wire and their entire path

 

[Number4]

As an electrician I can tell you that all your going to get by putting in a bigger fuse is a car fire. The best way to find out what is causing the draw is to break the circuit down into sections until you find resistance. This can be done by following the harness from the fuse to what the fuse is protecting and unplug the connectors in between until you find the short. Definitely not fun. Your meter will show you exactly where the problem is. You should only have 1-2 ohms in between two points provided your meter is good, any more than that and you probably have a short or it's going to ground. I don't have the manual you need but there are guys on here that have shop manuals that will give you the wire colors for every wire and their entire path

I second this. The fuse is designed to protect the circuit. This includes the end unit (stereo etc) as well as the wiring.
The wire size coincides with the fuse, designed for the fuse to blow before other damage occurs. Put in a bigger fuse and you will most likely melt your wires which is obviously a fire hazard.

 

[mikey8335]

Welcome aboard!!

The thread you posted in was almost 6 years old. I have taken your post and made a new thread in order to get better exposure.

Is it #15 under the hood in the Battery Junction Box or Fuse #15 under the dash in the Central Junction Box that keeps blowing?

 

[mikey8335]

Thanks Big Rondo, it's #15 under the dash