I have a 2003 ram 2500 4x4 5.7. When my ignition is turned off the rear brake lights dont work,they work with key on. When I press the brake peddle it wont come out of park? If I unhook the shifter cable park solenoid it will come out of park. I have replaced the brake light switch and that did not work? Checked fuses and all seems good.
I have been driving it the way it is with no problems, its the first vehicle I have owned with this feature?
But now I need to tow a trailer with electric brakes and they wont work? I have a digital brake unit and it wont send a signal to the trailer brakes unless I manually push the brake unit button.
Thanks in advance Kerry

 

Download the 03 Srvc Man from the links below in my sig and try looking around page 2327 for the 545rfe section. I would think the brake switch also since it has to send power somewhere to release the lock so you can change out of Park. If I get a chance later this morning I will look through it also

 

Thanks Weedahoe for the service manual and info!
I did the alignment test? on the brake interlock solenoid and it is working correctly. I can hear and feel the solenoid click in and out with the key switch. When unplugged it is unlocked when plugged in with the key on it is locked, it is suposed to unlock when the brakes are applied. But of course it does not? I have changed the brake switch and proved to myself the solenoid is working correctly. It has to be in the brake light wiring some where?? Any more help on this would be greatl!!
Thanks again Kerry

 

I have an 03 ram 1500 5.9L and it has the same problem. I have noticed that my brake lights will not work unless the key is turned to the run position. Also, I have no third brake light at all. Have you had any luck in finding your problem?

 

Had the same problem last week
the third brake lite works off the brake swich not the module and the other brake lites will not work unless the key is on or running
Open the hood on the left side pull the fuse cover and look for the fuse for the third brake lite bet its blown can't remeber what fuse # it was
Mike

 

Thanks for the info, I checked the fuses and #24 was blown. I replaced it and it fixed the third brake light and the rear brake lights not working with out the key on run. I have not hooked the BTSI back up to ceck that yet. I will do that later this weekend and let you know what happens.