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Discussion Starter · #1 ·
Hi, I am a new member and desperately need some guidance in helping me to learn what I have done wrong or could do better. All 3 of my brake lights would not work. Connections cleaned, fuses checked and bulbs replaced. Climbed under the dash and replaced the brake light switch. The result of that has landed me with all 3 brake lights consistently staying on. What have I done wrong? Please help.
2000 740il E38
 

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Society of the 7's East
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Disconnect switch the lights should go out. Make sure the switch isn't engaged when you installed it. In other words, adjusted correctly. As long as all lights are illuminated its not a problem from the switch back. My money is on the switch either being installed wrong ate defective.

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Discussion Starter · #4 ·
Thank you both. I disconnected the switch and the lights are still on?? I am currently under the dash trying to see where I went wrong.....
 

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Society of the 7's East
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All you did is swap the switch? Now with the switch disconnected the lights are still on? Do I have this right?

The only place B+(positive) gets to the lights in the back is thru the switch. If I am wrong please someone correct me.
 

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Discussion Starter · #6 ·
Yes. That's all I did. The original switch was replaced I am assuming when the recall happened. It has the white line on it. The new switch is from Napa and is different, but looks to be correct when comparing to pictures from other forum threads and Google. I threw in the towel for the night. Any suggestions would be appreciated. Thank you again.
 

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Society of the 7's East
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I suggest you start pulling the fuses one at a time to see which circuit is keeping those lights on. Do not pull the airbag fuse or else you will need the software to turn off the dash light.
All of the lights share the same positive wire in the center of the sockets. Find the color of the wires and trace them back to see what is energizing them. The brown wire is ground. If you can try to get this kamatics I know there's a place online that has E38 schematics.

This may sound crazy but you may want to put the old brake light switch in or at least plug it in to see if the lights still stay go out.

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You have the switch hooked up incorrectly. Review the diagram that came with the switch. Re install the old one and then try one more time to install the new sw. If that doesn't get it you can check the Sw with an ohm meter to see if it is defective. You can make a tester with a battery and a light bulb if you have to. The switch usually is just a simple open or closed device. with only two wires. remember that it is simply supposed to close the circuit when you use the brakes. if other wires are present they are secondary. Keep it simple. Craig
 

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Old switch=lights off. New switch =lights on. Therefore wiring from switch to lights =good, and old switch = bad.

You are not certain the new switch is correct. Therefore test off the car and replace with OEM if necessary, testing new one off the car as well. Install and adjust as required
 

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Discussion Starter · #10 ·
Thank you all. The switch came on its own, no instructions, in a small Napa box. I am going to try, as suggested and reinstall the old one and then the new again. I will also test to see if the switch is defective.
 
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