SN95 mustang brake switch wiring
01-04-2015, 09:58 AM
#1
SN95 mustang brake switch wiring So I have a BP automotive harness that needs a 12V signal when the brake is applied (to unlock converter). The brake switch on the car (95 mustang) is 12V when the brake is NOT applied and 0V when the brake is applied, exactly the opposite of what I need. Is there any device that can be installed to flip-flop these values so I don't have to install a different brake switch?
05-30-2015, 05:34 PM
#4
So after driving the car for a couple of months I figured it was time to address this issue.
First, my initial post above is incorrect. The brake switch on the mustang is normally open. One side of the switch is a constant 12v, the other side is 12v only when the brake is applied.
Second, the signal wire to the ecu needs a constant 12v and should open (0V) when the brake is applied.
So, how do I accomplish this? Can it be done with a simple relay? If so, I'm stumped. I guess wiring a simple relay either isn't the answer or its above my pay grade.
Here's what I have to work with, any help would be greatly appreciated.
First, my initial post above is incorrect. The brake switch on the mustang is normally open. One side of the switch is a constant 12v, the other side is 12v only when the brake is applied.
Second, the signal wire to the ecu needs a constant 12v and should open (0V) when the brake is applied.
So, how do I accomplish this? Can it be done with a simple relay? If so, I'm stumped. I guess wiring a simple relay either isn't the answer or its above my pay grade.
Here's what I have to work with, any help would be greatly appreciated.
05-30-2015, 05:51 PM
#5
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So after driving the car for a couple of months I figured it was time to address this issue.
First, my initial post above is incorrect. The brake switch on the mustang is normally open. One side of the switch is a constant 12v, the other side is 12v only when the brake is applied.
Second, the signal wire to the ecu needs a constant 12v and should open (0V) when the brake is applied.
So, how do I accomplish this? Can it be done with a simple relay? If so, I'm stumped. I guess wiring a simple relay either isn't the answer or its above my pay grade.
Here's what I have to work with, any help would be greatly appreciated.
First, my initial post above is incorrect. The brake switch on the mustang is normally open. One side of the switch is a constant 12v, the other side is 12v only when the brake is applied.
Second, the signal wire to the ecu needs a constant 12v and should open (0V) when the brake is applied.
So, how do I accomplish this? Can it be done with a simple relay? If so, I'm stumped. I guess wiring a simple relay either isn't the answer or its above my pay grade.
Here's what I have to work with, any help would be greatly appreciated.
Pin 87a to ecu
Pin 85 to brake switch hot when braking
Pin 86 ground
This will give you 12v when driving and 0 volts when pushin brakes.
05-30-2015, 08:48 PM
#7
Update: Everythings wired up. Took it for a test drive and...... it made no difference what-so-ever. I've been driving the car without the brake pedal/tcc connection for about 700 miles. I thought the tc had been locking but everything I read said it wouldn't lock without this connection.
Is there another input that the 411 ecu needs to control tc lockup on a 4L80E? FWIW, on the highway the tc does not unlock when you tap the brake (with some throttle applied simultaneously).
Is there another input that the 411 ecu needs to control tc lockup on a 4L80E? FWIW, on the highway the tc does not unlock when you tap the brake (with some throttle applied simultaneously).