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Discussion Starter #1
Driver’s side brake light has quit working and it is not the bulb and not a bad contact. Is there a separate circuit for the left and right sides power to the brake light coming off the brake pedal switch? Maybe a loose connection on that side? I see they both run off the same fuse so that is not the problem.

Thanks you.
Rich

1993 7.3 IDI F-350
 

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...not a bad contact.
How do you know?
Is there a separate circuit for the left and right sides power to the brake light coming off the brake pedal switch?
No, but there is at the MFS. Click this & read the caption:


(phone app link)


You can find your truck's wiring at this link:
BBB Industries- Premium Alternators, Starters, Power Steering Products | TSB's & Wiring Diagrams
It requires an e-mail, but it doesn't check that it's yours or even real.
 

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Discussion Starter #3
Break light not working one side only RESOLVED

Steve83, thank you very much!

This info was exactly what I needed since I didn’t realize that the MFS controlled the brake light. Here is what happened:

I’d been testing my brake lights without the power on as I often do when I hook up a trailer. (I test the turn signals first with power then the rest without power.) I didn’t realize that the left turn signal switch was engaged and had caused a bypass of the brake light circuit on that side (as designed). After your reply, I was able to do a root cause analysis knowing what the MFS does and asked myself if I had maybe done the above. Tried it and found that is exactly what happened. Brake light is good. Thanks again.

Rich
 
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