JEspinoza

A couple of days ago, I parked my car at a friend's apt. and it wouldn't start. Today, I found that it was the fuse located under the hood that is called "IGN" in the owners manual. It is a 50 fuse. I went out, bought another fuse, came back, and put it in. When I went to start the car, the fuse blew. I tried another fuse, same thing happened.

What could be causing my IGN fuse to keep blowing?

Thanks for any help that will help get my car rolling again.

LS1s R US

iTrader: (1)

May be the switch or a ground wire touching the body somewhere! Thats why a fuse blows it shorts to ground and the amps over flow the fuse!Also if ya have any interior componets or stereo equipment look back at that! Good Luck!

JEspinoza

I think it is indeed a short somewhere along the wire. How do you know when looking through the wire if you find the short?

I have no stereo equipment and haven't done any electrical work at all to the car.

RX-Ben

iTrader: (7)

Get a digital multimeter from Radio Shack that can display voltage and do continuity tests as well.

I had the same problem happen- I was showing very low voltage in the system but there weren't any obvious problems. Turn out there was something wrong with the alternator wire.

In any case, you'll want to do a continuity check between the post on the starter and a ground on the chassis (or the engine if it is grounded). If you have continuity then you have a short somewhere.

Check your system voltage as well. If it is low, or falls off a few volts over the span of a couple hours, you have a short as well.

Ben

wrencher

iTrader: (2)

Those are maxi fuses they power high amp draw componets, like relays & the fuse box. Does it pop when put in or when key is cycled on? Does the car have any add on electrical componets?

JEspinoza

Thanks for the input guys, I have much time to mess with it til Friday or Saturday though so i'll let you know

Wrencher:
When I put the fuse in it is fine. But I go inside the car and put the key in the ignition. As soon as I turn the key you hear "crack" (the noise the fuse makes when blowing) and I go check and its blown. I have no add on electrical components in the car, the electrical system is just stock. I do have headers though and it could be possible they rubbed against something and caused a short.

technical

Is the fuse black when you take it out?
There's a short to ground between the igition switch and the relay. You should be able to eyeball the wires since one or more is probably melted onto something.

FWIW, measuring continuity won't show a short, only an open.

JEspinoza

technical:
The fuses themselves are not black at all, especially the new one that I had bought and tried. They appear to be a very little bit black around the part inside where they disconnect, but that's about it. I only looked at the wires once when I was checking the car out and couldn't tell no obvious melts. Are you saying though that I should be able to see the short quite easily because of the melted wires? By any chance, do you know which color the wire is that leads to that fuse?

Thanks for your help!

technical

Yeah, I mean black inside where the fusible actually blows.
If they really aren't black, then the circuit is probably shorting but not to ground.
I don't know the colors by heart, but you should be able to see two wires either melted together, skinned, or possibly caught on a piece of metal e.g. dash support.

Keep looking because it might not stand out and smack you in the face. Last time I had one that I almost couldn't see until I moved the wires around and saw it from a different angle.

If you like, I can post a pic of what I'm describing when I get home.

JEspinoza

Technical:
Sounds good, tomorrow I will go and try to look at the wires. Do those wires just run from the fuse box, through the firewall, into the steering wheel dash? It would be great if you could post a pic so I could know what i'm looking for. Is there a way I can find out what color the wire is? Well I suppose it shouldn't matter that much if i'm just looking for a faulty wire of any kind really.

So when I actually find this wire that is faulty. What do I do? Do I just throw some electrical tape around it and call it a day?

Thanks again for your help technical, I am sorry I am not that good when it comes to electronics

technical

I'll post up when I get home.

When you do find the damaged wire you'll want to replace the damaged section with new wire by soldering some replacement wire into the circuit and finish up with some heat shrink tube. Especially if it's under the hood.

technical

Here's a couple of pics of two wires melted together. They're from a wire harness in a late model Chevy Pickup Diesel. As a matter of fact it was the ignition and hazard circuits. Basically the truck wouldn't shut off when the four ways were on.

You'll either will see this type of problem or they'll be skinned and touching the body. Take notice that from certain angles it doesn't look like they melted together. I pulled them apart a bit which is why they're bare now.

Photos

JEspinoza

Technical thank you for all your help

Can the wire that you use to solder the connections just be found at an auto store? Also, I assume that these wires only run from that fuse box to the steering wheel right? So in other words it shouldn't be too much through sift through.

Thanks again for your help and tomorrow i'll give it an inspection!