Brake Lights won't cut off
11-19-2009, 02:42 PM
#11
Join Date: Nov 2009
Location: Great White Sharks
Posts: 35
Almost has to be the brake light switch I would think. It is the ONLY thing that turns the brake lights on and it is a simple pressure switch that completes the circuit. It is also one of 2 things that cancel out the cruise, the other being the button. My suggestion is to test the switch with a DVOM for continuity with the pedal in the upright and depressed positions.
Edit- Forgot to ask, does it do it with the key off?
Edit- Forgot to ask, does it do it with the key off?
Last edited by Tempted; 11-19-2009 at 02:45 PM.
11-19-2009, 11:44 PM
#12
3rd Gear Member
Thread Starter
Join Date: Feb 2008
Location: Mechanicsville, Va
Posts: 684
The brake lights remain on no matter what unless the fuse is disconnected or the battery is disconnected. So yea they remain on when key is off. Family friend of mine that was a mechanic for many a years still thinks it might be the switch somehow. Funny Nuke brought up not taking it to Firestone bc my secondary vehicle that I was driving bc of the stang problems had the brakes lock up after they supposively replaced the rotors and pads. So yea will probably be going to dealership tomorrow.
11-20-2009, 10:07 AM
#13
4th Gear Member
Join Date: Mar 2009
Location: CA
Posts: 1,291
Not to be a jerk here, but are you sure we're talking about the brake lights and not the tail light? The only reason I ask is that I've had people mistakenly put the wrong bulb in the car and it ends up being the tail light circuit thats on.
If the brake lights are constantly getting power- there's definitely a short somewhere (either the switch or the wires running to the lights). The brake light circuit should only be complete when the switch is activated.
On a different note, it doesn't matter where you take your car. The quality of work has nothing to do with where he/she works. It comes down to the knowledge and care of the technician.
If the brake lights are constantly getting power- there's definitely a short somewhere (either the switch or the wires running to the lights). The brake light circuit should only be complete when the switch is activated.
On a different note, it doesn't matter where you take your car. The quality of work has nothing to do with where he/she works. It comes down to the knowledge and care of the technician.
11-20-2009, 10:53 AM
#14
6th Gear Member
Join Date: Feb 2007
Location: state of confusion
Posts: 7,635
So today as I was coming home I noticed that my cruise control wasn't working which was odd but when I got home I noticed that my brake lights won't cut off. I have spent over 2 hours trying to figure out what the problem is. I checked the fuse and that is fine. I believe I disconnected the wire to the brake switch but the light remained on. Just some background but it was raining today and I did have to slam on brakes at one point on the way home. I have never had the leaking problem and the floor isn't wet but I think it may have something to do with the slamming on the brakes. Let me know if anybody has any advice. I attached a picture of what I was looking at under the dash. I disconnected the wire leading to the blue thing which I believe is the brake switch.
Just disconnecting the brake pedal switch will not fix a problem caused by a short in the wires or their connector.
Norm
11-20-2009, 10:53 AM
#15
Cut & Paste Expert
Join Date: May 2007
Location: NW Arkansas
Posts: 13,322
when he clearly stated that he HAS the water leak issue.
The SJB is corroded beyond belief and disconnecting the brake switch wire
will do ZERO for turning off the brake lights.
The semiconductor(s) that turns on the brake lights has
an eddy current going thru the corrosion to the base(s) and keeps it turned on 24/7.
New SJB time for you...
Expect more electrical accessory gremlins in your near future...
Try engaging the cruise control at speed and if it works, it thinks the
brake switch is off. If it dont work, then maybe, maybe its the switch.
Last edited by 157dB; 11-20-2009 at 02:51 PM.
It WAS on the tip of my tongue but I was hesitant to mention it.
11-20-2009, 08:06 PM
#17
3rd Gear Member
Join Date: Mar 2006
Location: New Hampshire
Posts: 851
I cant believe everyone is blaming the brake light SWITCH
when he clearly stated that he HAS the water leak issue.
The SJB is corroded beyond belief and disconnecting the brake switch wire
will do ZERO for turning off the brake lights.
The semiconductor(s) that turns on the brake lights has
an eddy current going thru the corrosion to the base(s) and keeps it turned on 24/7.
New SJB time for you...
Expect more electrical accessory gremlins in your near future...
Try engaging the cruise control at speed and if it works, it thinks the
brake switch is off. If it dont work, then maybe, maybe its the switch.
when he clearly stated that he HAS the water leak issue.
The SJB is corroded beyond belief and disconnecting the brake switch wire
will do ZERO for turning off the brake lights.
The semiconductor(s) that turns on the brake lights has
an eddy current going thru the corrosion to the base(s) and keeps it turned on 24/7.
New SJB time for you...
Expect more electrical accessory gremlins in your near future...
Try engaging the cruise control at speed and if it works, it thinks the
brake switch is off. If it dont work, then maybe, maybe its the switch.
11-21-2009, 05:50 AM
#18
6th Gear Member
Join Date: Feb 2007
Location: state of confusion
Posts: 7,635
Is it just possible that that last hard braking event caused a specific pair of wires to become bridged by the shifting of a little corrosion product?
Norm
Last edited by Norm Peterson; 11-21-2009 at 05:53 AM.
11-21-2009, 07:28 AM
#19
6th Gear Member
I was a system engineer at a few nuke plants and have done a lot of troubleshooting in my day. It's very easy to jump to conclusions but it takes discipline to develop a test plan and then follow it. When you troubleshoot, you need to know what your expected results are for a normal condition and then pursue the reason for any unexpected result.
