I have a 09 Outback that has started blowing stop light fuses (brake lights. ) When this happens the ABS and traction control dash lights come on. I assume there is a short in the brake light wiring harness somewhere. I am not sure how the ABS is connected to this. I have replaced the 20 amp fuse twice. Today it blew out for the third time. The fuses work for about a week. I know when it has blown because the ABS light comes on. How do I try to track down the short?

 

Thanks

Check the brake light sockets and look for melted wire insulation where the wires go inside the socket. The sockets can get too hot and can melt the wire insulation. If you have a trailer wire harness check that also.

Thanks for your reply, Cougar. I pulled the taillight lens and looked at the wires, They are somewhat brittle, but I did not see any melting. I do not have a trailer wiring harness. The fuses have gone from lasting a week to going out almost immediatly.

The ABS light probably comes on because when the fuse pops, something else that is powered through that fuse (ABS related) now lost power.

 

Anyways, for tracking it down. It's hard to say without a reason.

 

Can you think of what you're doing when the fuse pops? Did you hit a bump? Take a corner kind of hard? Or simply cruising on the highway. 

The melted insulation happens inside the bulb socket and hard to see, if that is what is happening in your case, but there could be a different problem happening here. This is just a problem I have seen in the past that caused the fuse to blow out each time the pedal was pressed.

 

I assume the fuses are blowing out when you depress the brake pedal which passes power to the brake lights. If that is correct then disconnect both sides of the BL. I think you can leave the center one connected but if the fuse still blows you may have to disconnect that one also to eliminate it as the trouble. The trouble should be with one of the sides so when you reconnect one side at a time you will know which side has the trouble as you test each side. If the trouble is before the lights then disconnecting the lights will make no difference and the fuse would still blow out. You could use an ohmmeter to watch the resistance when you press the pedal down in place of the fuse placing one probe to ground and the other probe to the fuse connection that ties to the lights (the protected side).

CHeck the 3rd brake light and the pass through boot (wires) at the top of the tailgate.