Ignition key fuse keeps blowing

2004 MAZDA RX8
140,000 MILES • 2WD • MANUAL
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TY KEITH
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It keeps blowing ignition key fuse as soon as I turn the key . Not even try to turn it to crank the first turn of the key will blow the fuse. I’ve pulled all the wiring out and replaced some bad wires and it worked for about 30 minutes of driving and now it’s started back blowing the ignition key fuse.
Jul 16, 2020 at 2:24 PM
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ASEMASTER6371
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Good evening,

Can you tell me which fuse number is failing? I need that to see what it controls so we can get to the root cause of the failure.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Roy
Jul 16, 2020 at 2:54 PM
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KASEKENNY
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When you are saying it is blowing the ignition key fuse, I assume you are talking about the IG fuse? Basically the one that feeds the ignition relay? If so, this actually does not have anything to do with the key/ignition switch (most likely).

Take a look at the wiring diagram. As you can see this fuse feeds the ignition relay which ends up leading to the ignition condenser and coils. Most likely have a shorted wire but here is what I would suggest the easiest way in finding this. Go to the coils and unplug all of them and then the condenser. Turn the key back on and see if the fuse blows. If not, you have unhooked the issue. Then start plugging them back in one at a time and turn the key on and continue this until the fuse blows again. At that point, you either have a short in that component or the wiring too it.

Let me know if you have questions and we can go from there. Thanks
Jul 16, 2020 at 2:59 PM
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TY KEITH
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It is this one that keeps blowing ig key 15a . I’m going to try to unplug coils and condenser now.
Jul 16, 2020 at 3:13 PM
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ASEMASTER6371
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Okay, just to throw in my 2 cents. That wire goes to the ignition switch.

Disconnect the switch or just the yellow wire. It sends a feed out to the ignition system.

Roy
Jul 16, 2020 at 3:26 PM
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TY KEITH
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Unplugged coils and condenser and it still blows the fuse when I turn the key over. I’m going to try the ignition switch now . But how will I know if it blows if I can’t turn the key over without the switch plugged in.
Jul 16, 2020 at 3:30 PM
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TY KEITH
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I unplugged the switch with key turned on and it didn’t blow, but as soon as I plugged it back in it blew.
Jul 16, 2020 at 3:40 PM
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ASEMASTER6371
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See if you can pull the yellow wire out of the connector.

Then plug the connector back.

My thought is either wiring to the ignition switch or a possible switch.

Roy
Jul 16, 2020 at 3:42 PM
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TY KEITH
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I unplugged the yellow wire and it did not blow, but I replaced that whole wire yesterday because it was melted it worked for about 30 minutes then started popping fuses again.
Jul 16, 2020 at 3:46 PM
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TY KEITH
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Does the starter get any power on the first key turn ?
Jul 16, 2020 at 3:50 PM
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ASEMASTER6371
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No, it does not.

How far back did you replace the wire?

If it melted there, I would replace the switch as well.

Roy

IGNITION SWITCH REMOVAL/INSTALLATION

1. Disconnect the negative battery cable.
2. Remove the column cover.


imageOpen In New TabZoom/Print


image

3. Remove in the order indicated in the table.
4. Install in the reverse order of removal.
Jul 16, 2020 at 4:08 PM
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TY KEITH
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So I ran a wire from the battery straight to were the yellow wire would be and it works.
Jul 16, 2020 at 4:20 PM
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ASEMASTER6371
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Then you have a wiring issue between the fuse box and the ignition switch. You need to open the harness and inspect it for damage.



Roy
Jul 16, 2020 at 4:22 PM