Break light fuse blowing instantly
 

I have a 1997 Civic, the break lights were not working so I checked the fuse first. The car calls for a 15A fuse and had a burnt 20A fuse in it. I replaced the fuse but only had another 20A and not a 15A so I went ahead and put that 20A in, I hit the breaks, it turned on for a millisecond and the fuse blew... Any ideas whats going on?

They're aptly named "break lights".

The circuit is shorting to ground. Trace it looking for an exposed bare wire, pinched wiring, or a frayed wire.

You can also test it first with no bulbs in any sockets, then add each one and test it might help narrow down area that is shorted .

You may have a break in the brake lights?

It could be a water leak or corrosion causing a short, maybe?

I would start by checking the bulbs/sockets first. I have seen too many cars with incorrect/broken bulbs. I have also seen lots with corrosion. Then I would check for any aftermarket alarms, amps, subs and where they tied in to the vehicle wiring.

You can always put a paperclip in where the fuse goes and do a "smoke test." Just kidding! :D

Could also be a shorted out brake light switch, but more likely a poor connection or bare wire somewhere in the brake system.

First I would check the wires from the sockets as far back to the battery as you can and check from the fuse to out, also look under the dash and check from the break switch back. After that I would remove all bulbs replace the fuse and press the break check the fuse, then reinstall one light checking the socket for an obstruction and the bulb to make sure one of the contact wires is not crossing over shorting it out. From there keep adding one light at a time till it blows.

When it blows remove the last light you tried and add the next light leaving the one it blew on out and see if it happens again. If it blew on the last light (all installed) remove one or the previous lights and use it in the last socket (the one that blew it). If it blows the fuse this time you have located the one that is grounded out and you will need to check that socket and wiring from end to start.

If it only blows with all installed it is a draw problem and could be a PIA to find or could have some corrosion on/in the wires could have happened if there was a leak in the trunk at one time and it has wicked down the wire or could be on the engine/fuse box side with the same issue.

OK so I went out and bought another 4 fuses the other day so I can try to figure this problem out.

Try 1: Went outside and pulled out the brake bulbs and put a new fuse in, it blew instantly.

Try 2: I started looking around for noticeably odd wiring, and thought "Well if I can just get my 3ed brake light to work then It will atleast be more safe" so I looked at it and noticed it was unplugged and the wires that plugged into it was plugged into something else so I unplugged that and put a new fuse in.

Turned on the lights and the tails DO light up now! woot! :thumbup:

Now I just gotta go buy some bulbs because out of the 2 in the car and the extra 2 I had in the house, only 1 worked. I had another one that just did the low beam but not the high (for when you touch the breaks)

BTW: Horn works now too! yay

Good detective work. Congratz.