Odd electrical issues

Alright, during the day right now whenever I press my brake the radio and display lights dim

At night, when I have my headlights on, the radio and display lights are fine, but the brake light stays on even when I'm not braking.

I haven't made any changes to the electrical system (or any changes at all really).

Anyone have any ideas?

It's a 2005 Legacy GT Automatic

I'm hoping this is the correct section to post this to.

I assume that the radio lights dims when you turn on your position lights. That's since you usually turn on the lights during night and therefore it makes sense to dim the lights.

But if the radio lights dims when you press the brake I would look for a grounding fault by the tail lights first.

Also see if the position lights by the headlights goes on when you press the brake, that can be a clear indication of current taking the wrong path too.

And if the turn indicators also behave in a mysterious way then it's also a sign of something wrong.

There can be other causes too, but this idea is a good start.

One more thing - replace the tail light bulbs, since it may be that one of them actually has broken and caused a short between brake and parking light filament.

If you recently have replaced one of the bulbs, pull it out, turn it 180 degrees and insert it again since some have an asymmetrical construction.

Reflash the CPU. I know it sounds crazy, but I had a similar problem with the DR window (wouldn't work)

Checked out fuses, motor, wiring etc,etc. Could not find problem. Reflash,fixed.

might work. Who knows what evil lurks in the heart of the CPU:eek:

One more thing - replace the tail light bulbs, since it may be that one of them actually has broken and caused a short between brake and parking light filament.

 

If you recently have replaced one of the bulbs, pull it out, turn it 180 degrees and insert it again since some have an asymmetrical construction.

yea what he said ... i have seen this before

I should get a chance to work on this tonight.

I was out of town during the weekend.

Another strange symptom that I noticed is that my cruise control doesn't work when the headlights are on.

Reflash the CPU. I know it sounds crazy, but I had a similar problem with the DR window (wouldn't work)

 

Checked out fuses, motor, wiring etc,etc. Could not find problem. Reflash,fixed.

 

might work. Who knows what evil lurks in the heart of the CPU:eek:

How would I go about reflashing the CPU? Also, I have a Cobb APv1 if that impacts the steps to do so.

Another strange symptom that I noticed is that my cruise control doesn't work when the headlights are on.

Cruise Control goes off when you press brake pedal, so if you have current feedback through the brake lights then that's probably just another symptom.

How would I go about reflashing the CPU? Also, I have a Cobb APv1 if that impacts the steps to do so.

Reload whatever realtime Cobb (or whatever map) map you are using. If that doesn't work, load the cobb map as a new base map.