My '03 Legacy GT sedan has it brake dash light come on whenever the temp is below 30 degrees. Brake fluid is clear, and in between the max and min Mark. Brakes well, no ABS light. It goes out after 7 min of driving. Sometimes comes back on if hard braking.

That light is connected to a switch on the ebrake lever, and a level switch in the reservoir. Usually it just means slightly low fluid level. But the switch can be faulty.

 

If the fluid is definitely full, unplug the switch on the reservoir. If the light no longer comes on, it's that switch....

 

Switch alone is part #26456AC000, It is discontinued from Subaru, and no dealer in the US shows inventory. However, it looks like you can get one straight from Japan through Amayama: https://www.amayama.com/en/search?q=26456AC000

^good info right there.

 

I would also recommend changing out your brake fluid, unless you know its age. If it's got any water - it could contribute to the temp. sensitive level.

^good info right there.

 

I would also recommend changing out your brake fluid, unless you know its age. If it's got any water - it could contribute to the temp. sensitive level.

I changed it year half ago when replaced front caliper.

I'd expect the light would be on solid if you disconnected the float switch - but I'm not 'certain'.

 

most systems are made 'normally closed' so a break in wiring will 'announce itself' .

 

if you splash in even a just a tablespoon of brake fluid - it may make enough difference that the light stays off - if not, then investigate eslewhere.

 

also, what happens to your DRLs when the light is on? parking brake turns them off but low fluid wouldn't.

Edited February 1, 20179 yr by 1 Lucky Texan

The low fluid switch is definitely normally open. Unplugging it will disable it.

 

 

I know on one of the Subarus I had, low fluid disabled the DRLs. Don't remember which one. Although a quick look at my '04 diagrams, it's definitely the same wire from the parking brake switch, both just switched-to-ground and there's no diode, so I'm not sure how the DRL module would have any way of knowing which switch was activated.

 Just had the same thing on my 05. As stated above, just a splash of brake fluid did the trick.

There was no visible signs of leaks and the pads were only half worn.

shortlid,

 

I agree with Numbchux and brus brother. One of my past OutBacks had the same issue when it was extremely cold. It drove me crazy until I added brake fluid to the master cylinder to bring the level up to the Max line. Want things to expand ... add heat. Add cold ... things contract, just like the brake fluid volume in the reservoir. It shouldn't be that touchy at mid way between add and max, but it is a 14 year old car and deserves its character flaws.