Wierd brake light problem.
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Junior User
Joined: Aug 2001
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Wierd brake light problem.
I tried a search and so far no luck... so here goes..
I have a 97 F-150, V6, 5speed.
The rear brakes lights, all 3 of them will work with light pressure to the brake pedal. With medium and hard brake pressure the brake lights will turn off.
I changed the brake light switch today (the one on the brake pedal) and it made no difference.... same problem.
I checked the "brake pressure switch" on the master cylinder and it remains closed when there is light to moderate pressure on the brake pedal.. when I push hard on the brake pedal the switch opens....
basically here is what happens when i'm checking the brake pressure switch.
light brake, brake light turns on... switch is closed..... apply more brake pressure, brake light turns off... switch is still closed......really step on the brake, brake lights are still off but the switch opens (no contuinity).
btw.. the brake pressure switch was replaced by the ford dealer about 2 months ago when we brough it in for a broken cruise control.
I have a 97 F-150, V6, 5speed.
The rear brakes lights, all 3 of them will work with light pressure to the brake pedal. With medium and hard brake pressure the brake lights will turn off.
I changed the brake light switch today (the one on the brake pedal) and it made no difference.... same problem.
I checked the "brake pressure switch" on the master cylinder and it remains closed when there is light to moderate pressure on the brake pedal.. when I push hard on the brake pedal the switch opens....
basically here is what happens when i'm checking the brake pressure switch.
light brake, brake light turns on... switch is closed..... apply more brake pressure, brake light turns off... switch is still closed......really step on the brake, brake lights are still off but the switch opens (no contuinity).
btw.. the brake pressure switch was replaced by the ford dealer about 2 months ago when we brough it in for a broken cruise control.
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Junior User
Joined: Aug 2001
Posts: 55
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update.... I found the problem...... the wire that connects the BOO switch was broken.
I made a small pigtale to bypass the Boo switch and then proceded to slam on the brakes...... the brake lights did NOT turn off....... I then concluded that there was nothing else in the circuit (another switch) causing the brakes to go bad...... must be the boo switch....
I was then poking around underneath the dash when i discovered poking at my pigtale resulted in me being able to turn on/off the brake lightts....... a broken wire
.
As a "temp" fix I cut off the factory connector and replaced it with 2 female quick disconnects (which happen to fit perfectly on the switch)... the brake works fine now.
When I was working on the wires I noticed that they are really cheap wires that they broke easily
.... does anybody know where the other end of the wire leads to? how easy/hard would it be to replace the entire piece of wire with something better / more flexiable.
I made a small pigtale to bypass the Boo switch and then proceded to slam on the brakes...... the brake lights did NOT turn off....... I then concluded that there was nothing else in the circuit (another switch) causing the brakes to go bad...... must be the boo switch....
I was then poking around underneath the dash when i discovered poking at my pigtale resulted in me being able to turn on/off the brake lightts....... a broken wire
.As a "temp" fix I cut off the factory connector and replaced it with 2 female quick disconnects (which happen to fit perfectly on the switch)... the brake works fine now.
When I was working on the wires I noticed that they are really cheap wires that they broke easily
.... does anybody know where the other end of the wire leads to? how easy/hard would it be to replace the entire piece of wire with something better / more flexiable.
Senior User
Joined: Oct 2003
Posts: 299
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From: north carolina
i am not sure. in most cases the wire leads to a relay. from the relay it will go all the way to lights. the switch to the relay may not be that bad but from the relay to the lights will be a little harder.
furrby
furrby
