Why is the main fuse blowing?

The car was running fine, headed down the interstate, then it just died. We got it home, found out that the main fuse was blown (30 amp), and replaced it. Now every time I try it, as soon as I hit the starter the fuse blows again. Any ideas, cause I can't seem to find a short or anything. Thanks for any help.

Without basic info like year, engine size, any recent maintenance, etc. it's tough to say anything. Did you check the FAQ info or manuals at the top of the forum?

Sorry, had a brain fart or something. The car is a 2004 Camry with a 2.4 litre and normal routine maintence, nothing out of the ordinary oil changes etc. I thought about it being the starter, but could that have caused it to blow the fuse and die while traveling down the interstate? Thanks.

You could pull the starter, take it in and have it bench tested. Many auto parts places will do it for free; Kragen/Schucks are common where I live. This will answer the question about the starter health. Seems unlikely the starter was the original issue as the starter is not doing anything when cruising down the road. Although I have had similar experiences to what you describe with trying to start the car (without success)and traced it back to starter issues. I'd also suggest you get the codes read and see what the ECU is indicating.

Needed the year so I know which schematic you need from the links to the manuals at the top of the forum. This is from The "Factory Manuals" link at the top of the forum: http://oregonstate.edu/~tongt/camry/02/Starting_and_Ignition_I4.pdf

Considering you can't find a short anywhere the starter is a likely candidate to start with. You could remove it and have it tested instead of replacing it. Next would be the ignition switch or relay. Have you checked all connections for tightness and corrosion. Could cause an arc and voltage surge and blow the fuse. There's lots of info at the top of the forum. Just have to fish through it.

Remember the voltage to the starter is always hot. It's just looking for a ground.

Thanks for the replies. I'll try getting the starter tested first, hopefully it will be something simple. Like you said it's hot all the time, so who knows, it may have gone to ground while going down the road. I'll let you know what I find. Once again thanks.

Are you refering to the 30amp AM2 fuse?
Is it burning out when the ignition is turned on?
It looks like the 2004 has a condensor on AM2 also.
On my 92 that shorted causing this type of problem when the ignition is turned on.
I believe it is listed as a noise filter on the previous posts drawing.
Let us know what the outcome is.
Mine was $4 at dealer. No one else will carry that part.

Got it figured out today. It was sort of the starter. What was actually happening was that plastic cover on one of the wires had come loose causing it to short across the wires, thereby blowing the fuse and shutting the car down. Super easy fix, and not a penny spent on it. Hopefully that cover will stay intact, I'll be watching it closely. Thanks again everybody.

2004? Isn't it still under warranty?

Who cares? It's fixed and it was free (except for the cost of fuses) :)

2004? Isn't it still under warranty?

Warranty is out, unfortunately it has too many miles already.