I have a 2004 Ram 3500 dually 4x4. One morning I started it up and the brake light on the dash stayed on. Everything seems to be working fine.I took it to a local shop and they looked it over on the rack,pulled all the wheels and didn`t see anything noticable wrong. 6 months ago I had all new brake pads put on it. I pull a 35ft 5th wheel RV and need everything working good. I`ve gone over the whole truck and can`t find anything wrong..Does anybody know where I should go from here? Will a DRBIII scan tool tell just what is the problem? What about an OBDII scanner? can it tell me anything? I sure could use some input. Thanks

 

check fluid level.. and the plug for the sensor.. could be the sensor float in the master cylinder sticking.. open the top and take a pencil.. screwdriver or something and try to push it down see if it comes back up.. you can also tap on the side of the master cyl and see if it shuts off.. is the abs light on as well? or just the brake.. if the abs light is on .. you can use a drb3 tool and it will tell you if its a sensor or the abs module or whatnot

 

Thanks for the fast response.I`ll give it a try today and will let you know if that works.The ABS light is not on.Just the brake light.

 

Well I tried tapping on the mastercylinder,tried to push down the senser in the mastercylinder with a long screwdriver. I looked all under the truck for fluid leaks and saw nothing. I`m at a loss for answers.The only sensers I could find at the parts store are the ABS senser and the park brake switch. I`m wondering if I should try replaceing the park brake switch first. Anybody got a guess on what it could be? The ABS light doesn`t come on.Just the brake light on the dash.

 

Way back when I had the same problem. My cause was the parking brake switch. A little wiggle of the parking brake pedal solved my problem. Maybe yours too?

 

just because try looking at the ebrake possiablity that the pedal is not in contact with the switch or the switch may just need to adjusted that would illuminate the brake light.

 

i agree park brake switch