Ignition Fuse Keeps Blowing
 

OK, I did some searching, and nothing I came up with seems to quite match waht I'm having trouble with, so here goes:

Went to the mall this afternoon after a day of driving all over Phoenix/Tempe. Was inside for only an hour or so, and when I pulled out of the parking space, my 8 totally died while it was still rolling. I try to restart it, and nothing, so I think battery. I get out and push it into an open space, then pop the hood.

When I opened the door, I noticed that the dome and door lights came on nice and bright, and the ignition beeped to let me know the kesy were still in. Trunk popped and doors locked and unlocked with remote, but no dash lights except door ajar and security key light, no stereo, AC windows or sunroof, so I think FUSE.

in the fuse box, the only blown fuse was the INGNTION fuse, 15A, so I pull the cigarette lighter fuse to replace it, and the car runs like a champ. I hit AutoZone to get a set of fuses and replace the cigarette lighter. Then as I'm pulling out, car shuts down AGAIN. I replace the same fuse again, start the car, and turn everything off. I get maybe 20ft, and the car shuts down a 3rd time. I push it into a driveway and replace the 15A fuse with a 20 fuse, start it, and it ran fine all the way home (3 miles or so). I parked it and drove our Altima the rest of the day.

My questions:

1. Why is my car suddenly blowing fuses? It's an '04 that bought Jan 20th with 17k miles on it.

2. Will the 20 fuse cause problems? I know they put a 15A fuse in so that anything that exceeded that rating would blow the fuse rather than damage the car, but the 20 seems to be holding fine thus far.

Any ideas? Thanks!

i saw your sig, what aftermarket electrical equipment do you have?

If you've installed aftermarket electronic 's then it might be something of that nature has
shorted out. All I can say is if you had an electrical schematic just trace the wires. It sounds like the wire at the fuse (POSITIVE) is shorting to ground. Check the electrical system on that wire from the fuse and try to determine where the short is. Put a voltmeter on OHM's and see if the fuse is grounded. Both sides of the fuse terminal. Check continuity to ground. If it shows ground the you have a positive short to ground. Basically you will be checking continuity from one end of the wire to the other.Trace where that wire goes and look for a break in the wire and any cut through area's.
This is just a quick (maybe not) diagnosis of the problem.
I track electrical systems all day and I know it can be difficult. And I don't know if you want to try something like this or not.
Just a suggestion.
PM me if you need any more info.

My sig?

No mods at all. car is completely stock from what I know. I have a grounding kit still in the box in the trunk. No stereo or anything.

oneof the guys on my team just reminded me of a little incident like this I had when I tried to do the fog light mod right after I got the car, so Im gonna go check that out in a little bit, but if I wrapped everything up nice and tight and left no wiring exposed, why would I get this problem 2 months later?

Thanks for the help guys!

When the fuse blows up like this, you HAVE a short somewhere.

Check ur fog lights and see what happens. and DONT use fuse thats higher than what it was, u risk of overheating some wires (and who knows whats going to happen)

^ +1 not good to go over the specified current rating. Replacing a blown fuse with one under the current rating is fine if you don't have any replacements.

When the car died, where your fog lights on? Try running the car without the fogs and see if the problem still exists. You could cut the wire from the connector you made. If the problem still exsists you can always re-crimp the connector. This will make you %100 sure it isn't the fog light.


Found this post in the fog light DYI thread I think the fog lights are the culprit:

https://www.rx8club.com/showpost.php...6&postcount=72

:spank: if it's a six speed be sure there are no wires around the clutch area.(i have done this before by accident).also take a good long look at the wires you wraped and be sure they did not melt together...just sharing what i have done before that drove me nuts untill i found out what i had done ! :Eyecrazy:

Resurrected 2 1/2 years later!!!

So I'd apparently wired the fog lights incorrectly, and that was blowing the fuse back in March 2007. I got the car home, fixed the foglight mod, and I had no other problems with the fuse blowing until April 2009 when I started popping fuses again.

I took the car in to Berge Mazda here in AZ and told them the issue and a few other things going wrong with it (had the sunroof, stock Bose CD player, water pump, t-stat and t-stat housing, and radiator hoses replaced, and had an ECU flash for more oil injected into the engine).

The dealership told me that my reverse relay switch was going out, and that was causing the fuse to blow, so they replaced it. I got the car back April 9th, 2009 and it ran beautifully until the end of June when I blew another ignition fuse getting off the Freeway one night. Replaced it with a spare and limped it home with no problems, and then blew 4 more ignition fuses 2 days later.

I had it towed under warranty to Berge Mazda again last Wednesday. It's still there, and they still have no idea what's causing the fuse to blow.

This is really scary because when the fuse blows while I'm driving the car, the whole thing shuts down. Luckily so far it's only happened when I'm slowing down coming to a red light or stop sign, but I don't even want to drive with my kids in the car because I'd hate to have the fuse blow on the freeway or in an intersection one day. I saw a thread here about someone's STOP fuse blowing, and it sounded similar, but mine is blowing the ignition fuse, so it might be a different problem.

Any ideas? Please help!!!

My ignition fuse would blow every time I put it in reverse.

It took the techs at my dealership couple days to find it. It was the "reverse relay".

-Mr. Wigggles

The dealership fingered my reverse relay as the culprit as well and they replaced it (along with my water pump, t-stat and housing, and upper and lower radiator hoses, and my CD Player), but it blew the fuse a few weeks later again, so I took it back. They replaced the fuse, and kept the car a week trying to get it to blow again, but no dice, so they just gave me a break on teh diagnostic fee and gave the car back to me. Drove it for a month and now it's back at the dealership again getting the entire transmission replaced, along with the cracked front crank housing (?), and the ignition coil. $10,700 estimate for parts and labor. Thank God for my warranty! I think it might be time to part ways with my 8. :(

It's logical to assume if you didn't have a problem before you did the work, then you did something to cause a short.
Otherwise It's a pretty big coincidence.
Recheck it to see if you have any pinched or exposed wires.

Fuse
 

Does it start, or does it blow the fuse as soon as you turn the key on?
Try disconnecting it and see what happens

Doesn't sound like a short.
Be sure your ground is secure, and check to see if you have the right size fuse for the circuit.
Never go bigger than what you need, if you have to use a different size, go smaller until you figure out what's wrong.

Is the all wiring secure and properly crimped? It sounds like something is moving around and shorts on body metal when you brake, accelerate or take a turn.

Also how much current is this new stereo pulling? If the radio is off, does it still do this?