Hello,
I am hoping someone can help me b/c I cannot afford to take this to a mechanic. I have an 02 Elantra with 138,000 miles, this has been a great car with no problems until recently. My brake lights (all 3) stopped working and I replaced the stop fuse- (I believe its #16). Which worked and I realized that one of the bulbs was blown so I replaced that. This worked for about 5 days, then it blew again. This continued for a couple of weeks, now as soon as I put the fuse in it blows. The brake switch is good b/c I checked it when the fuse was working and I got power. I am assuming there is a short somewhere, but I just don't know where to start. Can someone please help???

 

Check the voltage output of the alternator before you do anything. It should be about 13.5 volts if you test at the battery with motor running, and 12.5 amps without motor running. Make sure you have correct amperage fuse in the fuse socket, should only be 10 amps.

 

OK, checked the amps and everything is ok there. I have been using 15 amp mini fuses, so I went on to hmaservice.com and pulled the schematics for this car and it does call for a 15 amp. However it also says the fuse is for the stop lamp,power window ETACM. This is a bit confusing since I am not having any issues with my windows.

 

Brake light switch is a good place to start. Even though it appears to be ok, it's the only moving part. They're cheap, and you could rule out that being the problem.

If it's not that, then you'll be lucky if it's a shorted wire. Look in the trunk for a pinched wire, like you put something heavy on it and pinched it.

Hopefully it's not a problem with the BCM, as that could be expensive and hard to troubleshoot.