First let me say that I've been lurking here for awhile, and it's easy to see that there are some really intelligent and helpful members here. Well, I really need some help. I have a new to me 2003 Ram 1500 regular cab, short bed Hemi. It is loaded with probably most, if not all options available at the time, including the tow package with an Odessey brake controller. Having just bought the truck, I've been in heaven enjoying it until yesterday, when I discovered that I sort of have NO BRAKE LIGHTS! The third brake light works as it should at all times, but the rear lights below the running lights do not work properly. They do work as they should when the ignition is OFF. If I turn the ignition to the RUN position (just before the starter engages), they come on and stay on. This is without touching the brake pedal. If I switch the key back one position then back to RUN, they will turn off and stay off until I touch the brake, then they stay on again, even when the brake is released.
If I leave ignition off and push the brake pedal or manually engage the brake controller, they work as they should. If I turn ignition to run, then off, then run, the brake controller will manually light the brakes as it should. If at any time I touch the brake pedal, the lights come on and stay on.
I've not found any fuse issues yet and I've taken the brake controller out of the system by unplugging it.(no change)
Not sure where to look next. Will try to disconnect rear 7 pin connector later today to see if that makes a difference.
Sure could use some ideas. Thanks - Lou

 

Sounds like your brake controller has a short. It's right on the pedal

 

Replace brake light switch by brake pedal.Easy fix

 

O.K. I'll visit the dealer and pick up a new brake switch. But after pulling the old one, I have to ask...how can a mechanical switch work the lights properly with the ignition off, but keep the brake lights on when the truck is running? I couldn't believe how easy the switch comes out. I even took it apart, expecting to see some mini circuit board or something, but it's just a mechanical switch, ( if you're familiar with the joke.... "how do it know?" ) And why is the switch stamped "Do not reinstall" ? I reinstalled it and it works the same as it did before. I'm really baffled by this and will really be scratching my head if a new switch cures the problem. I will find out tomorrow, if the dealer has one, and I'll post the results.
Thanks for the quick responses.

 

Well, you gentlemen were right on the money. Stopped at my dealer and picked up a new brake switch (just over $15. with tax) the parts guy said it is a pretty common problem, replaced the switch and everything works as it should. Still wish someone could explain how this thing works. It just doesn't make sense to me. Anyway, THANK YOU!!!! - Lou

 

Most brake switches have relays which provide constant power and transfer it only when the conatcs on the pedal switch touch one another. It's just a simple break in the negative line that turns them off. The contacts were probably worn out.
Anyways, everything works. Glad to hear